gsmtap: Add defintions for GSMTAP based remote logging

Often it is useful to have log statements from the osmocom programs
synchronized with protocol traces.  So rather than having to open the
pcap file with GSMTAP or other protocol data side-by-side with the
textual log of one or more network elements, we simply pass the log
lines around as GSMTAP messages, which can then be displayed in-order
and interspersed with the protocol messages inside wireshark.

Change-Id: I33ab530e10ef0311b6f80b731e61894f20b4b3e7
1 file changed