Simplify and rewrite README.md #12628
Description
Clean up and simplify READEME.md
- Remove duplicates
- Add badges for slack/discord
- Remove unmaintained community projects links
- Link to Coder registry
- link to modules, backstage-plugins and, envbuilder repos.
- @ericpaulsen @bpmct @kylecarbs @ammario add more suggestions
Probably:
- Sync README.md with https://coder.com/docs/v2/latest to prevent any drift.