5" touch screen Prusa MK3S mount

I loved the Raspberry Pi case and touch screen but I wanted to mount it on the top of my Prusa i3 MK3S. I also wanted access to the backlight switch on the back of it. So this remix does two things:

• Adds some posts and clips to attach it to the MK3s
• Adds an opening on the side to switch off the backlight