hardware: Add a piezo beeper

[mytechguyri]

one minor annoyance when using the OpenSpool Lite device... when you're scanning a spool of filament, you can't see the green light, because there's the spool of filament that you're scanning in the way.

would be nice to add a piezo beeper to the unit.... green led, 2 short beeps red led, 1 long beep.

Then there's some audio feedback to a successful scan.