Fix: More robust connect cmesh faces by vertices and sphere cmesh examples

[jmark]

Describe your changes here:

This PR introduces fixes/enhancements to make the join_by_vertices routine more robust regarding the value range of the input vertices. Besides that this PR makes the sphere cmesh examples more robust by applying the actual radius parameter at the end when the vertex information is stored in the cmesh object. For some use cases the radius gets extremely big, e.g. around 1e6, and the shell thickness, quite small, e.g. around 10. This might confuse the join_by_vertices routine. The fix is to determine the face connectivity on a reference sphere/shell with sane radius/thickness.

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[jmark]

@Niklas997
@Davknapp

Do you need any input in order to progress on the review? Please agree on who feels responsible for doing the review.

[Davknapp]

@Niklas997 @Davknapp

Do you need any input in order to progress on the review? Please agree on who feels responsible for doing the review.

I will do it

[Davknapp]

Some small changes, then we can merge.

[jmark]

Some small changes, then we can merge.

I like it! Done.