No notification for updated TLS server certificates
Description
As LetsEncrypt release server certificates just for an short time (<3 months), Gajim is complaining from time to time, that the certificate change. While this is true, the new one is also a valid certificate and no reason to alert the user.
Ordinary users are getting confused, if we ask them and ask about fingerprints, even if there is no security breach. So I recommend to disable the alert, by default.