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/RestoreFeature/RestoreFeature.swift

@@ -122,6 +122,7 @@ public let restoreReducer = Reducer<RestoreState, RestoreAction, RestoreEnvironm
           backupData: backupData,
           backupPassphrase: backupPassphrase
         )
+        try env.messenger.listenForMessages()
         return .success(.finished)
       } catch {
         return .success(.failed(error as NSError))