Port away from QNetworkConfigurationManager
QNetworkConfigurationManager was removed from Qt6 and it's better to check the status of the sync job anyway. Only two issues:
- The timeout in quotient is quite high so it might take up to one minute before the message appear.
- Only sync job are listened but since they are continuously done, this is not a big issue and other job are affected by the same issue of an high timeout anyway.
Fix #414 (closed)