Summary: the current YBA HA APIs are undocumented,We need to document these APIs which are well tested and ready to be consumed

Test Plan: wip

Reviewers: #yba-api-review, skurapati, dkumar

Reviewed By: #yba-api-review, skurapati, dkumar

Subscribers: dkumar, svc_phabricator, yugaware

Differential Revision: https://phorge.dev.yugabyte.com/D47913