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/mkdirp-classic/README.md

@@ -0,0 +1,18 @@
+# mkdirp-classic
+
+Just a non-deprecated mirror of [mkdirp 0.5.2](https://github.com/substack/node-mkdirp/tree/0.5.1)
+for use in modules where we depend on the non promise interface.
+
+```
+npm install mkdirp-classic
+```
+
+## Usage
+
+``` js
+// See the above link
+```
+
+## License
+
+MIT