Provide a mobile application menu

Summary:
Adds a right-hand-side application menu, based roughly on `frame_v3.png`.

This has the same icon as the left menu until we get real design in, but is functionally reasonable.

Test Plan: {F26170} {F26169}

Reviewers: chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T1960

Differential Revision: https://secure.phabricator.com/D4061

src/applications/base/controller/PhabricatorController.php

@@ -169,6 +169,11 @@ abstract class PhabricatorController extends AphrontController {
       $view->appendChild($page->renderFooter());
     }
 
+    $application_menu = $this->buildApplicationMenu();
+    if ($application_menu) {
+      $page->setApplicationMenu($application_menu);
+    }
+
     $response = new AphrontWebpageResponse();
     return $response->setContent($page->render());
   }
@@ -238,4 +243,8 @@ abstract class PhabricatorController extends AphrontController {
     return implode('<br />', $items);
   }
 
+  protected function buildApplicationMenu() {
+    return null;
+  }
+
 }