tools: add unit test for test-modemmanager-service.py
The tests spawn the service via GTestDBus framework and make some test API call while checking libmm interface to verify that informations are well propagated.
To be able to use the fresh built libmm typelib, I used a wrapper script to set GI_TYPELIB_PATH (because DBus activation process clean the environment so it is not possible to set it directly in the file)
Signed-off-by: Frederic Martinsons frederic.martinsons@sigfox.com