[Improvement] Release Notes workflow Quality of Life Improvement and Standardization

[peterzhuamazon]

Hi,

As of now, the consolidated release notes workflows has been automated using MarkdownTableWriter from pytablewriter.

There are, however, multiple aspects to be improved for the future.

1. The release notes is now in html format instead of the markdown, which add up complexity on maintenance and reduce readability without a render. Example: https://raw.githubusercontent.com/opensearch-project/opensearch-build/2.12.0/release-notes/opensearch-release-notes-2.12.0.md.
2. The workflow can compile either OpenSearch or OpenSearch-Dashboards consolidated release notes, but is not able to put them both together into one file. This add up efforts for the release manager to manually combine both into a final release notes PR.

We are looking for ways to resolve the above two issues with some quality of life improvements.

Thanks.

[bbarani]

@peterzhuamazon Do you have any recommendation?

[rishabh6788]

Will take a look.

[rishabh6788]

Fixed as part of PR #4627