Update documentation and handling to use a `crates/collab/seed.json` (#10874)

Updates `collab` to accept a `seed.json` file that allows you to
override the defaults. Updated the `README` in collab to just have
directions inside instead of redirecting the developer to the website.

Release Notes:

- N/A

Co-authored-by: Max <max@zed.dev>
efcd31c254Kyle Kelley committed on 4/23/2024, 12:41:31 PM· committed by GitHubparentae3c641
3 files changedLine totals unavailable