[review] call waiting network service query/enable/disable

[Aleksander Morgado]

Hey,

Until now, the only setup we did for the call waiting service was to
unconditionally enable URCs while the modem was enabled, but we were
not doing any specific setup with the network. This MR allows client
applications to query the status of the call waiting service, and also
request to enable or disable it.

https://gitlab.freedesktop.org/mobile-broadband/ModemManager/merge_requests/128

All these operations require the device to be registered in the
network, so even the service status query is defined as a method in
the ModemManager API, not as a property.

E.g.:

$ sudo mmcli -m 0 --voice-query-call-waiting
call waiting service is disabled
$ sudo mmcli -m 0 --voice-enable-call-waiting
operation successful
$ sudo mmcli -m 0 --voice-query-call-waiting
call waiting service is enabled
$ sudo mmcli -m 0 --voice-disable-call-waiting
operation successful
$ sudo mmcli -m 0 --voice-query-call-waiting
call waiting service is disabled


Comments welcome!

-- 
Aleksander
https://aleksander.es