Implement isin() (and in1d())

[ClaudiaComito]

Related

340

Feature functionality https://docs.scipy.org/doc/numpy/reference/generated/numpy.in1d.html

https://docs.scipy.org/doc/numpy/reference/generated/numpy.isin.html

[github-actions[bot]]

Branch features/450-Implement_in1d_or_better_isin created!

[mrfh92]

This is about an interesting functionality that is still missing.

Therefore, reviewed and kept within #1109

[mrfh92]

Could serve as a first issue for someone who already wants to start with a not so straightforward example.