Automate post release activities

[gaiksaya]

Is your feature request related to a problem? Please describe

Coming from #4750 (comment)

There are various post release activities that can be automated among the ones listed here: https://github.com/opensearch-project/opensearch-build/wiki/Releasing-the-Distribution#post-release

• Release Tags.
• Input Manifest Update.
• OpenSearch Build Release notes.
• Decrease the Build Frequency.
• Retrospective Issue.
• Helm and Ansible Playbook release.
• Upcoming Release Preparation.

Most of them are manual as of now.

Proposing to have a central workflow similar to promotion workflow #4753

Describe the solution you'd like

Keeping in mind to keep the workflows as independent as possible, the right approach would be have individual workflows for each of the above points and only trigger them via central workflow.

• Release Tags - Already automated
• Update input manifest with tags Automate: Update the manifest refs to tags. #2546
• Automate consolidated Release notes  #4880
• Decrease the Build Frequency - We do this mid-release when RC is finalized. Need to reconsider if this is post release activity
• Retrospective Issue - Can be easily added using gh cli on GHA or jenkins. Automate retrospective issue creation #4849
• Helm and Ansible Playbook release - Have version increment PRs in each repo that should be triggered via central workflow using repository dispatch
• Upcoming Release Preparation - Can be manual

Describe alternatives you've considered

Continue manual chores. Better ideas and feedbacks are welcome.

Additional context

No response

[gaiksaya]

Keeping helm and ansible auto-increment as manual for now due to changelog complications.
Thanks!