This implements initial functionality to use QMI modem(s) as wireless WAN.
Only one modem at the time acting as WAN is currently supported. The expected setup is just one modem - i.e. Turris router with LTE kit - but code can handle multiple attached modems.
In that scenario all detected modems are offered as a choice, but there can be only one selected and designated as WAN.
Following API functions are currently implemented:
- get_settings
- update_settings
This MR depends on functionality implemented in: foris-controller!125