clips for the anycubic kossel alu profiles

These should clip right into the x-profiles (and be able to slide a bit). The LED-strip clip was a quick hack on request, haven't been able to test the tolerances yet.

original tested and printed w. 0.2 mm layer height, every thing designed to be printed without supports.

edit: tightened up the original clip, added experimental clip allowing the simple pi bumper (https://www.thingiverse.com/thing:3401335) to be clipped to the frame. Btw, I recommend using two, not one as shown in the demo pic.

edit: added ball joint socket clip for the ball joints here: https://www.thingiverse.com/thing:3412413