Implement most Differential actions against ApplicationTransactions

Summary: Ref T2222. Implements the simpler actions (abandon, reclaim, close, reopen, plan changes, request review) in a transactional way with validation and effect checks.

Test Plan:
  - Rigged submissions to point at the Pro controller.
  - Rigged dropdown to have all these options all the time.
  - Tried to apply about 20-30 of these operations to various revisions and always got the expected result (success, error, or no-op).

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2222

Differential Revision: https://secure.phabricator.com/D8307