noaa-apt demodulation integration

[dom-robinson]

This needs broader testing, but introduces NOAA-APT integration to RN2 for demodulation of NOAA images as an addition to wxtoimg.

I have left it as a 'draft PR' since until someone is interested enough to test it and able to beta test the ansible deployment I can't quite be bothered to work out how to make ansible get the install of NOAA-APT done 'properly' directly from the authors website (which feels like the 'proper' thing to do rather than redistribute his files as outlined below.

How it works:
i have added Noaa-APT's binary to the software folder and that is installed to the usr bin. Adding 'apt' to the noaa enhancement list will launch the new noaa_apt.sh script that in turn will run the wav file through NOAA-APT.

There is a to-do here; Noaa-APT requires that the 'res' folder that is included in the /software commit here, is available IN THE /srv/audio/noaa folder to be able to generate map overlay. I don't know, without recompiling the source, how to make the noaa-apt look elsewhere for that res folder. The software clearly calls for ./res/shapefiles/states.shp

Setup:
At the moment if you pull this draft PR you additionally simply have to manually copy the
~/raspberry-noaa-v2/software/noaa-apt binary and the
~/raspberry-noaa-v2/software/res/ folder to
/srv/audio/noaa

If anyone wants to work out the ansible effort to make this simply part of the install then all you should need to do is add 'apt' to the enhancement list in settings.yml