Add Seq Packing in NeMo / Neva2
<!-- pylint-output-strict-mode-false -->

beep boop 🤖: 🙏 The following files have warnings. In case you are familiar with these, please try helping us to improve the code base.

---

Your code was analyzed with PyLint. The following annotations have been identified:

```
************* Module nemo.collections.llm.peft.api
nemo/collections/llm/peft/api.py:38:0: C0116: Missing function or method docstring (missing-function-docstring)
************* Module nemo.collections.multimodal.data.energon.base
nemo/collections/multimodal/data/energon/base.py:88:0: C0301: Line too long (120/119) (line-too-long)
************* Module nemo.collections.multimodal.data.energon.config
nemo/collections/multimodal/data/energon/config.py:25:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/multimodal/data/energon/config.py:32:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/multimodal/data/energon/config.py:80:0: C0115: Missing class docstring (missing-class-docstring)
************* Module nemo.collections.multimodal.data.energon.task_encoder
nemo/collections/multimodal/data/energon/task_encoder.py:15:0: W0611: Unused import dataclasses (unused-import)
************* Module nemo.collections.vlm.neva.data.config
nemo/collections/vlm/neva/data/config.py:22:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/data/config.py:32:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/data/config.py:40:0: C0115: Missing class docstring (missing-class-docstring)
************* Module nemo.collections.vlm.neva.data.lazy
nemo/collections/vlm/neva/data/lazy.py:67:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:72:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:115:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:120:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:134:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:161:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:236:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:246:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/data/lazy.py:419:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:478:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/data/lazy.py:560:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:579:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:582:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/lazy.py:585:4: C0116: Missing function or method docstring (missing-function-docstring)
************* Module nemo.collections.vlm.neva.data.mock
nemo/collections/vlm/neva/data/mock.py:29:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/data/mock.py:76:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/mock.py:109:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/mock.py:114:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/data/mock.py:119:4: C0116: Missing function or method docstring (missing-function-docstring)
************* Module nemo.collections.vlm.neva.model.base
nemo/collections/vlm/neva/model/base.py:481:0: C0301: Line too long (139/119) (line-too-long)
nemo/collections/vlm/neva/model/base.py:484:0: C0301: Line too long (128/119) (line-too-long)
nemo/collections/vlm/neva/model/base.py:509:0: C0301: Line too long (123/119) (line-too-long)
nemo/collections/vlm/neva/model/base.py:93:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:139:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:155:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:176:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:243:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:255:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/model/base.py:282:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:303:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/model/base.py:334:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:371:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:384:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/model/base.py:896:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/vlm/neva/model/base.py:913:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:917:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:949:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:952:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:955:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:959:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:965:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:972:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/vlm/neva/model/base.py:48:0: W0611: Unused get_batch_on_this_context_parallel_rank imported from nemo.collections.llm.gpt.model.base (unused-import)
nemo/collections/vlm/neva/model/base.py:48:0: W0611: Unused get_packed_seq_params imported from nemo.collections.llm.gpt.model.base (unused-import)
************* Module nemo.lightning.megatron_parallel
nemo/lightning/megatron_parallel.py:238:0: C0301: Line too long (127/119) (line-too-long)
nemo/lightning/megatron_parallel.py:239:0: C0301: Line too long (140/119) (line-too-long)
nemo/lightning/megatron_parallel.py:240:0: C0301: Line too long (130/119) (line-too-long)
nemo/lightning/megatron_parallel.py:546:0: C0301: Line too long (129/119) (line-too-long)
nemo/lightning/megatron_parallel.py:553:0: C0301: Line too long (135/119) (line-too-long)
nemo/lightning/megatron_parallel.py:829:0: C0301: Line too long (137/119) (line-too-long)
nemo/lightning/megatron_parallel.py:1059:0: C0301: Line too long (136/119) (line-too-long)
nemo/lightning/megatron_parallel.py:1632:0: C0301: Line too long (128/119) (line-too-long)
nemo/lightning/megatron_parallel.py:1671:0: C0301: Line too long (146/119) (line-too-long)
nemo/lightning/megatron_parallel.py:64:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:65:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:67:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:102:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:106:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:306:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:330:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:356:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:382:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:518:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:561:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:565:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:619:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:654:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:660:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:666:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:673:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:680:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:714:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:722:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:738:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:765:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:777:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:799:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1325:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1500:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:1506:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1512:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1516:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1521:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:1526:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:1554:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1600:8: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1622:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:1695:0: C0115: Missing class docstring (missing-class-docstring)
nemo/lightning/megatron_parallel.py:1741:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/lightning/megatron_parallel.py:1755:0: C0116: Missing function or method docstring (missing-function-docstring)

-----------------------------------
Your code has been rated at 9.46/10
```

---

Mitigation guide:

* Add sensible and useful docstrings to functions and methods
* For trivial methods like getter/setters, consider adding `# pylint: disable=C0116` inside the function itself
* To disable multiple functions/methods at once, put a `# pylint: disable=C0116` before the first and a `# pylint: enable=C0116` after the last.

By applying these rules, we reduce the occurance of this message in future.

Thank you for improving NeMo's documentation! [🤖]: Hi @yaoyu-33 👋,

We wanted to let you know that a [CICD pipeline](https://github.com/NVIDIA/NeMo/actions/runs/12774637365) for this PR just finished successfully

So it might be time to merge this PR or get some approvals

I'm just a bot so I'll leave it you what to do next.

//cc @pablo-garay @ko3n1g
# What does this PR do ?

Add a one line overview of what this PR aims to accomplish.

**Collection**: [Note which collection this PR will affect]

# Changelog 
- Add specific line by line info of high level changes in this PR.

# Usage
* You can potentially add a usage example below

```python
# Add a code snippet demonstrating how to use this 
```

# GitHub Actions CI

The Jenkins CI system has been replaced by GitHub Actions self-hosted runners.

The GitHub Actions CI will run automatically when the "Run CICD" label is added to the PR.
To re-run CI remove and add the label again.
To run CI on an untrusted fork, a NeMo user with write access must first click "Approve and run".

# Before your PR is "Ready for review"
**Pre checks**:
- [ ] Make sure you read and followed [Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md)
- [ ] Did you write any new necessary tests?
- [ ] Did you add or update any necessary documentation?
- [ ] Does the PR affect components that are optional to install? (Ex: Numba, Pynini, Apex etc)
  - [ ] Reviewer: Does the PR have correct import guards for all optional libraries?
  
**PR Type**:
- [ ] New Feature
- [ ] Bugfix
- [ ] Documentation

If you haven't finished some of the above items you can still open "Draft" PR.


## Who can review?

Anyone in the community is free to review the PR once the checks have passed. 
[Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md) contains specific people who can review PRs to various areas.

# Additional Information
* Related to # (issue)
