Update readme and docs

[tmorrell]

❤️ Thank you for your contribution!

Description

Invenio communities has been in production for a long time, so it's no longer experimental. I also added some new readthedocs configs to try to get the docs to render again.

Checklist

Ticks in all boxes and 🟢 on all GitHub actions status checks are required to merge:

• I'm aware of the code of conduct.
• I've created logical separate commits and followed the commit message format.
• I've added relevant test cases.
• I've added relevant documentation.
• I've marked translation strings.
• I've identified the copyright holder(s) and updated copyright headers for touched files (>15 lines contributions).
• I've NOT included third-party code (copy/pasted source code or new dependencies).
  • If you have added third-party code (copy/pasted or new dependencies), please reach out to an architect on Discord.

Reminder

By using GitHub, you have already agreed to the GitHub’s Terms of Service including that:

1. You license your contribution under the same terms as the current repository’s license.
2. You agree that you have the right to license your contribution under the current repository’s license.

[fenekku]

LGTM. Is there a way to preview the readthedocs, before I search for it myself?

[tmorrell]

There isn't a way to preview readthedocs if it isn't configured correctly (like the state of this repo currently)...and it still might not work after merging this PR. The CERN folks are working on readthedocs permissions but without readthedocs repo access it's not an easy thing to debug.