Could not create the Preferences Core Data container in the App Group
because sub-directories did not exist. Create them upfront when using
App Group URLs.
This was not an issue with other Core Data containers because they are
stored in the app directories, where "Library/Documents" already exists.
Replace favorites entities with a PreferencesManager, that returns
observables for:
- Module preferences (by module UUID)
- Provider preferences (by ProviderID)
Automate preferences availability in:
- Module views (empty for now)
- VPN server view (favorites)
Synchronize preferences by making this a CloudKit container. Preferences
are also available in the Tunnel by storing the container in the App
Group.