R1:898ce6bace59

Search Symbols by Repository, not Project

Summary:
Fixes T7977.
- Move Indexed Languages and See Symbols From config to Repository
- Make symbol search skip projects

This also makes the default languages to Everything instead of Nothing.

Test Plan:
- Browse files, click symbols.
- Use quick search to find symbols
- Browse revision, click symbols

Reviewers: joshuaspence, epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Maniphest Tasks: T7977…