Add getGroup to ConfigOptions

Summary: Adds core and apps grouping to configuration options, makes it somewhat easier to browse config options.

Test Plan: Set each option, review list. Breakdown is nearly 50/50 apps/core.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11722

src/applications/files/config/PhabricatorFilesConfigOptions.php

@@ -15,6 +15,10 @@ final class PhabricatorFilesConfigOptions
     return 'fa-file';
   }
 
+  public function getGroup() {
+    return 'apps';
+  }
+
   public function getOptions() {
     $viewable_default = array(
       'image/jpeg'  => 'image/jpeg',