Add Shairport to Octoprint Image

Whenever imaging OctoPrint, most often due to my own error, I'm always adding Shairport post-process. Would be awesome to have it added to the image, permitting music to jam to while printing. Not a huge thing, but a nice to have!

I don't think that Shairport will be included in the official octopi image because it just get additional packages if they're needed for octoprint.
Some packages are even removed from the raspbian image (which octopi is based on).

But you can build your own image anytime :slight_smile: