R1:8fd20e82fcc6

Improve Conduit performance of special edge-based custom Revision fields

Summary:
Ref T11404. Depends on D16351. Currently, both `differential.query` and `differential.revision.search` issue `2N` queries to fetch:

- dependencies for each revision; and
- projects for each revision.

Fix this:

- Take these custom fields out of Conduit so they don't load this data by default.
- For `differential.query`, put this data back in by hard coding it.
- For `differential.revision.search`, just leave it…