Create the GSM network at the end of the init, send the
GSM reset on each reconnection and close a small window
when we would send a SCCP msg before being authenticated.
For that we have introduced an authenticated into the bsc_msc
struct and will manage it inside the bsc_msc_ip.c
Create a BSC<->MSC interface and use it for the BSC MSC IP and the
BSC NAT to reduce code duplication on handling reconnects to the MSC
and cleaning up the local state. The code is only partially tested
and will contain bugs. Currently both the BSC and the NAT will just
exit on connection loss and this way have the current behavior.