HyperCube Evolution Nut Remix (changed X and Y carriages)

These are adapted X and Y carriages from the [thing by bezeen](https://www.thingiverse.com/thing:2814140). I am using 8mm rods for the X/Y axes, so they are both for the LMU8 linear bearings.

Y Carriage: one of the M3 nut holes of the original Y Carriage was a bit too narrow for the nut to fit in, so I widened it to 6mm (same as the other holes). And also moved the holes closer (by 4mm) to the clamp so I can use shorter bolts.

X Carriage: narrower holes for the nut inserts (4.2mm instead of 4.7mm)