Add unnecessarily detailed splitter demo

[theRealSuperMario]

Hey guys,

I have had some struggles understanding how to get a regular split operation to work with an "arbitrary polygon".

So I thought that maybe someone might benefit from not having to go through my struggles and I created a small demo notebook.

Would be happy if this finds its way into the demos codebase.

Cheers 🍻

[tpaviot]

great contribution, thank you @theRealSuperMario