Modernize remaining edge types

Summary: Modernize remaining edges to subclass `PhabricatorEdgeType`. Largely based on D11045.

Test Plan: Browsed around and performed various actions include subscribing, unsubscribing and watching.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D11116

src/applications/project/controller/PhabricatorProjectWatchController.php

@@ -45,7 +45,7 @@ final class PhabricatorProjectWatchController
           break;
       }
 
-      $type_member = PhabricatorEdgeConfig::TYPE_OBJECT_HAS_WATCHER;
+      $type_member = PhabricatorObjectHasWatcherEdgeType::EDGECONST;
       $member_spec = array(
         $edge_action => array($viewer->getPHID() => $viewer->getPHID()),
       );