Add Raspberry Pi CM4 iPad Retrofit board

[geerlingguy]

Hackaday user Evan is retrofitting an original 2010 iPad with a Raspberry Pi CM4.

He's aiming to integrate the CM4 with all the original parts, including sound, touchscreen, bluetooth, controls, and the dock port (though likely using USB instead of Lightning? Not sure).

[EvanKrall]

I'm planning to use the original 30-pin dock port (the 1st gen iPad predates Lightning). I thought about doing USB-C and/or micro HDMI, since you could fit those where the 30-pin connector goes, but decided to stick with original hardware as much as possible.