Add basic edit history to herald rules

Summary:
Add a very basic edit history table to herald rules.  This table is updated
whenever saving a herald rule.  The contents of the save are not examined, and
the edit history contains no information about the rule itself *yet*.  Edit
history can be viewed by anyone through /herald/history/<rule id>/.

Task ID: #

Blame Rev:

Test Plan:
Made a test rule, saved some stuff.

Revert Plan:

Tags:

Reviewers: epriestley, jungejason

Reviewed By: epriestley

CC: zizzy, aran, xela, epriestley

Differential Revision: https://secure.phabricator.com/D1387

src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php

@@ -283,6 +283,7 @@ class AphrontDefaultApplicationConfiguration
         ),
         'new/(?:(?P<type>[^/]+)/)?$' => 'HeraldNewController',
         'rule/(?:(?P<id>\d+)/)?$' => 'HeraldRuleController',
+        'history/(?P<id>\d+)/$' => 'HeraldRuleEditHistoryController',
         'delete/(?P<id>\d+)/$' => 'HeraldDeleteController',
         'test/$' => 'HeraldTestConsoleController',
         'all/' => array(