Add pir_motion_detection_autoplay plugin

[Kanabanarama]

Retrying #278 with error fix

This plugin works with common PIR (passive infrared) motion sensor boards and starts playing if a motion was detected. There are two modes, one continues the queue and one starts a dedicated playlist defined in the plugins settings. I also added options to add a hardware switch to turn off motion detection more easily and a status LED, showing if motion detection is active and indicating motions by blinking.