Summary:
Ref T2543. Converts the TYPE_STATUS transaction (used to render "This revision now requires changes to proceed.", "This revision is accepted and ready to land.", etc) to ModularTransactions.
Also, continue consolidating all the status-related information (here, more colors and icons) into a single place. By the end of this, we may learn that NEEDS_REVIEW uses //every// color.
Test Plan:
Reviewed old status transactions (unchanged) and created new ones (looked the same as the old ones).
(I plan to migrate all of these a few diffs from now, around when I change the storage format.)
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T2543
Differential Revision: https://secure.phabricator.com/D18410
