Real-time Chat (#7664)

* feat(realtime-chat): add Pusher library to the server

* feat(realtime-chat): only for private groups

* feat(realtime-chat): add authentication endpoint for Pusher

* feat(realtime-chat): client proof of concept

* fix typo in apidoc

* feat(realtime-chat): redo authentication and write integration tests

* remove firebase code

* fix client side tests

* fix line ending in bower.json

* feat(realtime chat): use presence channels for parties, send events & disconnect clients if user leaves or is removed from party, automatically update UI

* pusher: enable all events in the background

* fix pusher integration tests

website/client/js/controllers/guildsCtrl.js

@@ -1,7 +1,7 @@
 'use strict';
 
-habitrpg.controller("GuildsCtrl", ['$scope', 'Groups', 'User', 'Challenges', '$rootScope', '$state', '$location', '$compile', 'Analytics',
-    function($scope, Groups, User, Challenges, $rootScope, $state, $location, $compile, Analytics) {
+habitrpg.controller("GuildsCtrl", ['$scope', 'Groups', 'User', 'Challenges', '$rootScope', '$state', '$location', '$compile', 'Analytics', 'Pusher',
+    function($scope, Groups, User, Challenges, $rootScope, $state, $location, $compile, Analytics, Pusher) {
       $scope.groups = {
         guilds: [],
         public: [],