Add Clustering Example by Network Distance

[miili]

Thanks for this comprehensive library.

I found and old example of yours, which interesting for our organization of field work.

https://github.com/gboeing/network-clustering/blob/main/network-clustering-simple.ipynb

I would love to see this as part of this repo. Adapted to the newer API.

Thanks and best wishes,

Miili

[gboeing]

@miili I'll aim to add this prior to the release of OSMnx v2.0