[Feature Request]: Create a search location for projects

### What would you like to happen?

Just like you can search all files in your project (pipelines, workflows, metadata, conf files, ...) it would be nice to have the Projects plugin contribute a search location for all projects and environments.

### Issue Priority

Priority: 3

### Issue Component

Component: Other

Start by locating the existing search-location mechanism for files, pipelines, workflows, metadata, and configuration files, then inspect how the Projects plugin exposes projects and environments. Define the integration points for including both project and environment entries, and verify that they appear in project search results.

Written by the indexing model from the issue text.