Fix proposed by Laurent.
The problem is in a server socket, that I think have been developed to send AT commands to the OAI UE. We let the feature in place, the problem was that they restricted the socket bind to localhost, that doesn't always exist. We bind the socket to any_addr (instead of localhost), so the commands to the UE can come also from a remote machine.
I've added also a
docker-compose to test locally the fix.