vertical cable guide 3U

3U Vertical cable guide for network racks

While the STL from coco_98 prints fine, the file is an absolute mess with lots of artifacts, cavities and double surfaces.
I completely remodeled the part in onshape and made some small changes:
- adjusted the length so one can actually line up more than 2 of these (part was too long for 3U)
- centered the holes and hooks so the part is symmetric
- enlarged the holes to 5.8mm to allow for some tolerances; the original design was almost a press-fit for the bolts...
- rounded off the edges to prevent cable damage (especially for fiber patch cords)
- made the hooks a bit longer and deeper, so they can hold more cables.

The design is also available at onshape: https://cad.onshape.com/documents/71ccdd7a8972960c00a3110a/w/ab8d17789cb27cf0a5161004/e/4909568447bd45766a1a8719