[WIP] Restructure into multiple instances

[pavithraes]

Reference Issues or PRs

Closes #359 Addresses #435

This pull request:

• Moves the "Community" pages into a separate instance, with a separate sidebar
• Creates a new instance for Nebari Slurm docs
• Updates top navbar to mention new projects
• Misc clean-up and consistency fixes

TODOs before merging

• [ ] Verify internal links are not broken by this change

Comments

• For reviewers:
  • I suggest starting with the preview
  • Ref: https://docusaurus.io/docs/docs-multi-instance
• Merge the currently open PRs before this one. This PR affects many pages and might disrupt ongoing updates.

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