Update diarization folder structure
# What does this PR do ?

This PR updates the folder structure of example/speaker_task/diarization  folder.

<img width="369" alt="image" src="https://user-images.githubusercontent.com/13211483/187006224-6ac5993b-e6b2-4ac2-85d5-c66208850983.png">


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

ASR (speaker tasks)

# Changelog 
- yaml files in diarization example folder
- changed the names in the diarization example folder.
- changed related parts in docs
- updated yaml paths in tutorials 

# Usage

Usage can be found in README.md file in example diarization folder


# 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?
- [x] 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)
