Add functionalities related to aromatic rings

[padix-key]

This PR adds the find_aromatic_rings() and find_stacking_interactions() functions to biotite.structure, that can be used to identify atoms that are part of aromatic rings and find pi-stacking interactions between them, respectively.

[codspeed-hq]

CodSpeed Performance Report

Merging #751 will not alter performance

_{Comparing padix-key:rings (99f3bd9) with main (d7df095)}

Summary

✅ 59 untouched benchmarks

[Croydon-Brixton]

Just fyi: This might be of interest to look at here: https://prolif.readthedocs.io/en/stable/

[padix-key]

Thanks, I also stumbled upon it during my research and adapted the cutoff distance from it.