Improved random seed configuration for Lhotse dataloaders with docs
Thanks @erastorgueva-nv, for some reason I thought it's required by sphinx. It should look much better indeed! Docs LGTM
# What does this PR do ?

* Comprehensive documentation about random seed configuration, behavior, and effects on dataloading.
* Backward-compatible changes to random seed configuration in training.
* Allows more precise control over randomness; this work was triggered by the need to support mixed data-parallel (DP) and tensor-parallel (TP) training. Before this PR, it wasn't possible to configure the dataloader to yield identical data on identical DP ranks but different TP ranks, causing deadlocks. Now it's possible but the user has to be careful about manually setting different random seeds on training continuations (this is documented).
* Unit tests to ensure the desired behavior in DDP setups.

**Collection**: ASR

# 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 
```

# Jenkins CI

The Jenkins CI system has been replaced by GitHub Actions self-hosted runners.

There's no need to comment `jenkins` on the PR to trigger Jenkins CI.
The GitHub Actions CI will run automatically when the PR is opened.
To run CI on an untrusted fork, a NeMo user with write access must 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**:
- [x] New Feature
- [ ] Bugfix
- [x] 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)
