Migrate a bunch of admin routes to ES6 modules

app/assets/javascripts/admin/controllers/admin-backups-index.js.es6

@@ -1,8 +1,8 @@
 export default Ember.ArrayController.extend({
   needs: ["adminBackups"],
   status: Em.computed.alias("controllers.adminBackups"),
-  isOperationRunning: Em.computed.alias("status.model.isOperationRunning"),
-  restoreDisabled: Em.computed.alias("status.model.restoreDisabled"),
+  isOperationRunning: Ember.computed.alias("status.model.isOperationRunning"),
+  restoreDisabled: Ember.computed.alias("status.model.restoreDisabled"),
 
   uploadLabel: function() { return I18n.t("admin.backups.upload.label"); }.property(),
 

app/assets/javascripts/admin/controllers/admin-backups.js.es6

@@ -1,5 +1,5 @@
 export default Ember.ObjectController.extend({
-  noOperationIsRunning: Em.computed.not("model.isOperationRunning"),
-  rollbackEnabled: Em.computed.and("model.canRollback", "model.restoreEnabled", "noOperationIsRunning"),
-  rollbackDisabled: Em.computed.not("rollbackEnabled")
+  noOperationIsRunning: Ember.computed.not("model.isOperationRunning"),
+  rollbackEnabled: Ember.computed.and("model.canRollback", "model.restoreEnabled", "noOperationIsRunning"),
+  rollbackDisabled: Ember.computed.not("rollbackEnabled")
 });

app/assets/javascripts/admin/controllers/admin-customize-css-html.js.es6

@@ -1,13 +1,5 @@
 import showModal from 'discourse/lib/show-modal';
 
-/**
-  This controller supports interface for creating custom CSS skins in Discourse.
-
-  @class AdminCustomizeCssHtmlController
-  @extends Ember.Controller
-  @namespace Discourse
-  @module Discourse
-**/
 export default Ember.ArrayController.extend({
 
   undoPreviewUrl: function() {