Breaks up the ARC documentation into several smaller articles.
`@vijay-train` and `@martin389` put together the plan for this update, and I've just followed it here.
In these updates:
- The README has been updated to include more general project information, and link to each new article.
- The `detailed-docs.md` file has been broken up into multiple articles, and then deleted.
- The Actions Runner Controller Overview doc has been renamed to `about-arc.md`.
Any edits to content beyond generally renaming headers or fixing typos is out of scope for this PR, but will be made in the future.
Co-authored-by: Bassem Dghaidi <568794+Link-@users.noreply.github.com>
Ken Muse
Thorsten Wildberger
Siara