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/promise/polyfill.js

@@ -0,0 +1,10 @@
+// not "use strict" so we can declare global "Promise"
+
+var asap = require('asap');
+
+if (typeof Promise === 'undefined') {
+  Promise = require('./lib/core.js')
+  require('./lib/es6-extensions.js')
+}
+
+require('./polyfill-done.js');