Index definitions for type-search on all branches

[ChrisPenner]

Overview

• TODO fix codebase owner calculation for contributor branches in the DB trigger

Adds the mechanism to index arbitrary branches for definition search, not just releases.

Implementation notes

• Adds a new definition search indexing queue that operates based on the root branch hash rather than release
• Add triggers to project branches and releases to add to this queue
• Always index branch and release pushes, but also copy releases into the global search queue when relevant.
• TODO Add new endpoints for searching within a project branch.

Test coverage

• Existing transcripts
• New transcripts for project branch searching