Fixing the linker error, updating from docs-beta to official document…

[khushbr]

Is your feature request related to a problem? Please provide an existing Issue # , or describe.
Fixing the linker errors:

1. Updating from docs-beta to official documentation post launch.
2. Excluding https://www.envoyproxy.io/ from link checker. It is failing with too many redirects

Linker Errors from upstream 'main' run:

Errors in README.md
✗ https://docs-beta.opensearch.org/monitoring-plugins/pa/index/ (HTTP status client error (404 Not Found) for url (https://docs-beta.opensearch.org/monitoring-plugins/pa/index/))
✗ https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/ (HTTP status client error (404 Not Found) for url (https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/))

Errors in src/main/java/org/opensearch/performanceanalyzer/rca/store/rca/temperature/README.md
✗ https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/ (HTTP status client error (404 Not Found) for url (https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/))

Errors in src/main/java/org/opensearch/performanceanalyzer/rca/README.md
✗ https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/ (HTTP status client error (404 Not Found) for url (https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/))

Errors in docs/gauntlet.md
+ echo
✗ https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/ (HTTP status client error (404 Not Found) for url (https://docs-beta.opensearch.org/monitoring-plugins/pa/reference/))
+ echo ::set-output name=exit_code::2

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Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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