Remove "admin page" color/styles

Summary: These haven't had any effect since the redesign, and we're moving to a more granular policy model so it probably doesn't make sense to ever restore them.

Test Plan: Grepped for "admin" and removed all relevant code.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D3710

src/applications/base/controller/PhabricatorController.php

@@ -139,11 +139,6 @@ abstract class PhabricatorController extends AphrontController {
     $view = new PhabricatorStandardPageView();
     $view->setRequest($this->getRequest());
     $view->setController($this);
-
-    if ($this->shouldRequireAdmin()) {
-      $view->setIsAdminInterface(true);
-    }
-
     return $view;
   }