Docs: Consider surfacing remaining docs from repo Markdown files on the website

[JoshuaKGoldberg]

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• I have looked for existing open or closed documentation requests that match my proposal.
• I have read the FAQ and my problem is not listed.

Suggested Changes

Spiritual successor to #5242, and following up on https://github.com/typescript-eslint/typescript-eslint/pull/5762/files#r994711306: there's still a lot of information stored in .md files checked into the repo. But we've been directing users to the website -- which makes a divide between two areas of docs.

I propose we make the website the primary and mostly only place to view documentation, including type descriptions such as parserOptions. That would include guides for contributing and release strategies.

For that many users would expect to be in the repo, I propose we leave them where they are and configure Docusaurus to surface them -- as we've done for rule docs in #5249. The files to leave in-place are:

• ./.github/*.md
• ./*.md
• ./packages/*/README.md

Thoughts?

Affected URL(s)

Potentially many!

[bradzacher]

Related to #5090?