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.
Davide