Nema14 mounts for POLAR DRAWBOT

Mount for the POLAR DRAWBOT with additional holes for using nema14 motors. As I suspected, they are enough to drive the drawbot and I had a coupe laying around. Mirror the STL to have both sides.

I also made holes in the parts I used to be able to insert the captive nuts afterwards instead of having to pause the print.

I use a sanguinololu as a control board, modified firmware is available here: https://github.com/reefab/Makelangelo-firmware