Cantilever Laser Engraver fixes

I slightly increased the distance between the rollers on the Y-gantry, so the 2020 rail fits better. I also made two of the holes in the lower gantry plate bigger for eccentric nuts, like in the upper plate.

Also added a mount for my laser module, for endstop switches, a supporting wheel for the free cantilever arm, a fan mount and a spacer for the wheels where no eccentric nut is used.

Also added a Ultimaker Controller 2004 LCD holder.

I will publish a more extensive writeup on my website https://www.xythobuz.de soon!