Messenger - restore from backup

XXMessengerClient

• Add MessengerRestoreBackup function wrapper
  • Restore CMix and UserDiscovery from backup
  • Return restored params and contacts
• Add MessengerIsListeningForMessages function

xx-messenger example

• Restore backup from file
• Refactor app startup

Examples/xx-messenger/Sources/AppFeature/AppEnvironment+Live.swift

@@ -90,7 +90,6 @@ extension AppEnvironment {
       welcome: {
         WelcomeEnvironment(
           messenger: messenger,
-          dbManager: dbManager,
           mainQueue: mainQueue,
           bgQueue: bgQueue
         )