This allows implementing UI mechanisms to transfer the audio of a call
to the HF (pipewire) only when the user explicitly asks/allows it.
Normally, when a call is connected, the phone initiates a SCO connection
and the HF accepts it, transfering audio automatically. In order to
allow for user interaction, this patch enables the UI to set the RejectSCO
property to 'true' in order to automatically reject the SCO connection.
Later on, at the UI's discression, the audio may be reconnected by calling
the Activate() method, which sends AT+BCC to re-initialize the SCO channel.
A configuration file option is also added to configure the default value
of the RejectSCO property. By setting this to 'true' in the config file,
it is possible to implement rejecting the audio of a call that is already
active at the time the Bluetooth connection to the phone initializes.
This is useful for implementations that do hardware offloading of the
SCO audio channel and need to communicate state information to the
hardware (at least).
Start call id at 1 as for the index calls in HFP, and move this id
to spa_bt_telephony_[ag|call] so they can be used by CLCC to retrieve
the related call.
if enhanced call status is supported, send AT+CLCC on +CIEV events to
get the calls information.
