R1:1f86c7342881

Simplify policy filtering for projects and ObjectQuery

Summary:
Ref T603. Moves to detangle and optimize how we apply policies to filtering objects. Notably:

- Add a short circuit for omnipotent users.
- When performing project filtering, do a stricter check for user membership. We don't actually care if the user can see the project or not according to other policy constraints, and checking if they can may be complicated.
- When performing project filtering, do a local check to see if we're…