[DOC] - Remove `Releases.md`

[pavithraes]

Preliminary Checks

• [X] This issue is not a question, feature request, RFC, or anything other than a bug report. Please post those things in GitHub Discussions: https://github.com/nebari-dev/nebari/discussions

Summary

We have a new release process documented here: https://www.nebari.dev/docs/community/maintainers/release-process-branching-strategy

We can have the documentation page (at nebari.dev) as the source of truth and move undocumented details from the governance repo to the official docs. :)

Steps to Resolve this Issue

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