Cut arbitrary shapes into an indentation

[Rocka84]

This adds the possibility to cut shapes in an indentation. This was already possible for cylindrical compartments but not for arbitrary shapes.

[EmperorArthur]

I'm a bit confused just looking at the comments, and the cutter functions (excluding holes) are one of the few areas of code I haven't really examined in depth.

Would you mind sharing a few images of what this looks like.

[Rocka84]

Here you go, this is the example I added to gridfinity-rebuilt-bins.scad

and a bin for sd-cards and micro-sds