Add a workflow for documenting features

[VachaShah]

Is your feature request related to a problem? Humans have to remember to document features, or at least to open issues in documentation-website for new features/changes to be documented. This is a manual process, e.g. https://github.com/opensearch-project/OpenSearch/issues/1711#issuecomment-1060893992

What solution would you like? Add a workflow for creating issues in the documentation-website repo whenever a label needs-documentation is added on a PR. Refer: https://github.com/opensearch-project/OpenSearch/pull/2929

What alternatives have you considered? Create issues manually in the documentation-website whenever a feature needs to be documented.

Do you have any additional context? Add any other context or screenshots about the feature request here.