CSP Tools
# What does this PR do ?

Add cluster validation tests for cloud service providers to NeMo Megatron directory.

**Collection**: nemo_megatron_launcher

# Changelog 
- For all CSPs
    - DCGM diagnostics test job
    - NCCL tests build job
    - NCCL `all_reduce_perf` test job
    - NCCL topology file
    - All-in-one run script (cluster_validation.sh)
- AWS, additionally
    - Dockerfile on top of NeMo Megatron container with AWS EFA drivers

# Usage
See NeMo Megatron README (Cluster Validation section)

# Before your PR is "Ready for review"
**Pre checks**:
- [x] 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)
