Implementing an emergency stop type function, triggered by GPIO Pin.

[Dntyfight]

Hey, im currently writing my Bachelors thesis, automating the Printers in my Company.
As I am implementing an automated bed clearing mechanism, I need to issue an Emergency Stop to continues print via a GPIO Pin, when clearing fails.

I would like to have the option, of adding a pin that when set high, stops the cue and waits for restart.

Other Basic plugins only issue a general machine stop gcode command.

Thank you for your great job implementing this plugin!