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/level-packager/abstract/error-if-exists-test.js

@@ -0,0 +1,13 @@
+'use strict'
+
+var location = require('./location')
+
+module.exports = function (test, level) {
+  test('test db open and use, level(location, options, cb) force error', function (t) {
+    level(location, { errorIfExists: true }, function (err, db) {
+      t.ok(err, 'got error opening existing db')
+      t.notOk(db, 'no db')
+      t.end()
+    })
+  })
+}