[DOC] Performance Analyzer Documentation update

[khushbr]

What do you want to do?
Update PA Documentation at https://opensearch.org/docs/latest/monitoring-your-cluster/pa/index/. Specific section needing update:

1. Disable PA under https://opensearch.org/docs/latest/monitoring-your-cluster/pa/index/#install-performance-analyzer
2. Storage under https://opensearch.org/docs/latest/monitoring-your-cluster/pa/index/#storage. Re-phrase as prerequisite.

• 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.
All version

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