Add Basic Auditing Functionalities

Summary:
add basic auditing functionalities. For the related commits for a
package, we detect the following conditions which might be suspicious to the
owners of the package:

* no revision specified
* revision not found
* author not match
* reviewedby not match
* owners not involved
* commit author not recognized

The owners of the package can change the status of the audit entries by
accepting it or specify concern.

The owner can turn on/off the auditing for a package.

Test Plan:
*  verified that non-owner cannot see the details of the audit and cannot modify
it
*  verified that all the audit reasons can be detected
*  tested dropdown filtering and package search
*  verified really normal change not detected
*  verified accept/concern a commit
*  tested enable/disable a package for auditing
*  verified one audit applies to all <commit, packages> to the packages the
auditor owns
*  verified that re-parsing a commit won't have effect if there exists a
 relationship for <commit, package> already

Reviewers: epriestley, nh

Reviewed By: epriestley

CC: aran, benmathews, btrahan, mpodobnik, prithvi, TomL, epriestley

Differential Revision: 1242

src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php

@@ -303,6 +303,11 @@ class AphrontDefaultApplicationConfiguration
         ),
       ),
 
+      '/audit/' => array(
+        '$' => 'PhabricatorAuditEditController',
+        'edit/$' => 'PhabricatorAuditEditController',
+      ),
+
       '/xhpast/' => array(
         '$' => 'PhabricatorXHPASTViewRunController',
         'view/(?P<id>\d+)/$'