Settings: ask telephony for network selection

When configuring profiles and selecting a network mode override, ask
Telephony to provide the UI for showing the proper network modes. After
the user has selected it, we receive the result, and save it in the
profile.

Ref: CYNGNOS-1463

Change-Id: I866ed1bc1c915ae00804b07dbbafa86e679a5fa7
Signed-off-by: Roman Birg <roman@cyngn.com>