[DOC] Create documentation for Enhancement of Repository Plugin

[ashking94]

This is a placeholder for documentation addition/update that we will be required as part of opensearch-project/OpenSearch#6354.

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.
As part of feature proposal of enhancing the repository plugin, this will assist in documentation of the same.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

[ashking94]

Closing this since #2994 has been created.