Make PhabricatorRepositoryCommmit schema changes for audit

Summary:
  - Add a proper mailKey field to make these things mailable. Backfill all
existing objects.
  - Denormalize authorPHID to the commit object so we can query by it
efficiently in a future diff. We currently use the search engine to drive
"commits by author" but that's not so good for audit, which needs more
constraints.
  - Add an overall audit status field so we can efficiently query "commits that
needs your attention".
  - Add enough code to convince myself that these fields are basically
reasonable and work correctly.

Test Plan:
  - Ran schema upgrades. Checked database state afterward.
  - Ran "reparse.php --owners --herald" to verify worker changes.
  - Looked at a commit, altered aggregate status via audits / reparse.php,
verified it responded correctly.

Reviewers: btrahan, jungejason

Reviewed By: jungejason

CC: aran, epriestley, nh

Maniphest Tasks: T904

Differential Revision: https://secure.phabricator.com/D1706

src/applications/diffusion/controller/commit/DiffusionCommitController.php

@@ -268,6 +268,11 @@ class DiffusionCommitController extends DiffusionController {
       $props['Differential Revision'] = $handles[$revision_phid]->renderLink();
     }
 
+    if ($commit->getAuditStatus()) {
+      $props['Audit'] = PhabricatorAuditCommitStatusConstants::getStatusName(
+        $commit->getAuditStatus());
+    }
+
     $request = $this->getDiffusionRequest();
 
     $contains = DiffusionContainsQuery::newFromDiffusionRequest($request);

src/applications/diffusion/controller/commit/__init__.php

@@ -7,6 +7,7 @@
 
 
 phutil_require_module('phabricator', 'applications/audit/constants/action');
+phutil_require_module('phabricator', 'applications/audit/constants/commitstatus');
 phutil_require_module('phabricator', 'applications/audit/editor/comment');
 phutil_require_module('phabricator', 'applications/audit/query/audit');
 phutil_require_module('phabricator', 'applications/audit/storage/auditcomment');