util: update utility functions from StreamedMedia to Call
call-channel: add call-instance property
call-channel: fix up set_call_instance and connect to modem state changes
call-channel implement HardwareStreaming property
call-channel: use the correct handle when starting outgoing call
call-channel: add more debug context for when accepting calls fails
call-channel: register the channel on the bus

This took way way too long to debug.
call-channel: set the CallState to active when the call goes active
call-channel: declare GQueue requests as a single item array