Remove all reads of `ReleephProject->repositoryID`

Summary:
Ref T3655. ReleephProject currently has both `repositoryID` and `repositoryPHID`, which point to the same object and are reudundant. Get rid of all reads of `repositoryID`.

NOTE: This makes project loads depend on repository loads. The eventual rule here will be that you must be able to see a repository in order to see projects for that repository, which seems like a reasonable rule. We might need to tailor it more than this (e.g., if there are branch read permissions down the line) but this seems like a reasonable minimum.

Test Plan: Grepped for `repositoryID` in `releeph/`. Called `releeph.getbranches`.

Reviewers: btrahan

Reviewed By: btrahan

CC: LegNeato, aran

Maniphest Tasks: T3655

Differential Revision: https://secure.phabricator.com/D6633