Set up and run non-experimental tests on the CI

[kintel]

We should run tests for non-experimental OpenSCAD builds regularly.
Suggestion:

• Add config to Build and test OpenSCAD in non-experimental mode for one system/variant for each of Linux, Windows and macOS
• Run non-experimental tests weekly, perhaps choose a different day per platform

[kintel]

As we continue further Manifold integrations, the Manifold build and the CGAL build continues to diverge. Not running tests regularly on the non-Manifold (non-experimental) build significantly increases the risk of us breaking something in very hard to fix ways.

-> we should probably prioritize this. At least getting the build running on a single platform.