inform user if connection does not work because time is out of synch

If the time is out of sync with the time of a contact, one cannot connect with them over bluetooth (haven't checked it with wifi/internet)

There is no further information in the app, why the connection fails and so it difficult for a user to detect and correct the issue.

Time out of sync might happen often through the following:

• battery empty
• battery unplugged
• user has a spare phone that they haven't used since long and they just start it to test briar

If connection does not work because time is out of sync, the user should receive an inapp information.