Prusa MK42 Bed for Hypercube

I cut a notch in the original (now old) bed cable clip of a Prusa MK2, I also moved the cable "holder" from center to the side. All this to accommodate a Prusa MK2 bed clone on a [Hypercube](https://www.thingiverse.com/thing:1752766).

Normally the bulky Z LM12UU parts get in the way, with this part they should not.

The other difference is that I don't have the bottom piece - I find it redundant on a CoreXY - I just screwed it from the top and held with a nut from the bottom.