HyperCube Evolution XY idler

The tension of the belts caused the original XY idlers to slightly move after a while, maybe re-tensioning the bolts would have prevented this. However, it ended up in a lot of friction for the X axis when Y moved all the way back. This design (inspired by [this design](https://www.thingiverse.com/thing:2856944)) does not allow any movement once fastened to a 3030 extrusion profile.

To print this with a minimum of supports, the part should be placed on the build plate with the open ends down as shown in the image. It uses the same brass inserts as the original design.