[FEATURE] allow for audio direct processing

[stdevPavelmc]

We do an audio capture to temp and then process that to get the desired audio quality.

Some users have expressed the possibility of processing all the audio stream in a pipe, I have done that but if the SBC/PC has another task running this could ruin your capture, I have done that.

But I will expose it as a optional feature in the users.conf file, by default with a temp file, at code level it's something like this

timeout $5 rtl_fm -p "${RTL_PPM}" -f "${FREQ}M" -s "${rxbw}" \
			-g 44.5 -E deemp -F 9 - | \
			sox -t raw -r "${rxbw}" -e signed -b 16 -c 1 - ${WSATP}.wav rate 11025