Add CageMakerPRCG Parametric Rack Cage Generator

https://github.com/WebMaka/CageMakerPRCG looks like a very cool utility for OpenSCAD that will take in any device dimensions (like a random switch or mini PC), and output a rack cage you can 3D print for it.

From the README:

It's a tool designed by @WebMaka and he has a [Patreon](https://www.patreon.com/webmaka) if you want to show support for free tools like this.

Start by reviewing the linked CageMakerPRCG project and the mini-rack repository's contribution guidance. The issue does not identify files, entry points, acceptance criteria, or how the external generator should be integrated, so the expected result needs to be clarified before implementation.

Written by the indexing model from the issue text.