OpenSCAD R4 trigger prototype

[tomas-pecserke]

This PR show ´, how parts could be defined using OpenSCAD. To take full advantage of OpenSCAD, following tasks need to be prototyped as well:

• [ ] Automatic export to STL (natively supported by OpenSCAD)
• [ ] Automatic export to STEP (e.g. via FreeCAD python interface)

Feel free to ignore BOSL directory - it's a library.

[marcos-diaz]

Closing since we have now a repository for prototypes