Revert "Use memoryStorageDriver (#85)"

This reverts commit b8a7f6d.

Author: krassowski

lite/jupyter-lite.json

@@ -7,8 +7,6 @@
     "settingsStorageName": "JupyterEverywhere Storage",
     "exposeAppInBrowser": true,
     "showLoadingIndicator": true,
-    "enableMemoryStorage": true,
-    "contentsStorageDrivers": ["memoryStorageDriver"],
     "settingsOverrides": {
       "@jupyterlab/mainmenu-extension:plugin": {
         "menus": [