FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/immediate/lib/nextTick.js

@@ -0,0 +1,11 @@
+'use strict';
+exports.test = function () {
+  // Don't get fooled by e.g. browserify environments.
+  return (typeof process !== 'undefined') && !process.browser;
+};
+
+exports.install = function (func) {
+  return function () {
+    process.nextTick(func);
+  };
+};