Update menu item names for Applications -> Favorites

Summary: Adds a `MenuName` method to applications that `ProfileMenuItem` uses instead of the application name if set. This improves the home/menu/new user experience at little cost. Also renamed the label from Applications to Favorites, since this menu gets altered to provide more than just applications. This also allows instances to set back to Maniphest if they so choose. Overall I think this direction resolves 95% of my concerns, with maybe a small potential downside which I don't really anticipate. We already name Dashboard panels by their object, and that hasn't really caused confusion. I think these links are similar. I click 'Tasks' and get presented a list of my tasks from Maniphest.

Test Plan: Review each of the name changes as a default new install and a modified install.

Reviewers: epriestley, amckinley

Reviewed By: epriestley

Spies: Korvin

Differential Revision: https://secure.phabricator.com/D18524

src/applications/diffusion/application/PhabricatorDiffusionApplication.php

@@ -6,6 +6,10 @@ final class PhabricatorDiffusionApplication extends PhabricatorApplication {
     return pht('Diffusion');
   }
 
+  public function getMenuName() {
+    return pht('Repositories');
+  }
+
   public function getShortDescription() {
     return pht('Host and Browse Repositories');
   }