Add FIX/NO FIX logs

[Razican]

Currently, the GPS does not log if the fix is acquired or lost. We should log it for better debugging.

[Razican]

This should be an easy fix for newcomers:

only need to modify GPS 3 parsers in gps/GPS.cc so that when the fix is lost (there was fix but now there isn't) or recovered (there was no fix but now there is) the logger is invoked and a simple message is written.