docs: Remove local collaboration docs (#45301)

This PR removes the docs for running Collab locally, as they are
outdated and don't reflect the current state of affairs.

Release Notes:

- N/A

README.md

@@ -20,7 +20,6 @@ Other platforms are not yet available:
 - [Building Zed for macOS](./docs/src/development/macos.md)
 - [Building Zed for Linux](./docs/src/development/linux.md)
 - [Building Zed for Windows](./docs/src/development/windows.md)
-- [Running Collaboration Locally](./docs/src/development/local-collaboration.md)
 
 ### Contributing