Feature: implement Community Detection with network_g2g()

[martinctc]

Problem

Currently, the network_g2g() only returns a network visual, and there are no complementary methods to derive more insights around it.

Suggested solution

An new function or an option that identifies group-based communities in a group-to-group network. One option is to use the Louvain method to maximise modularity, where modularity would be the measure of the strength of division of a network into modules (or clusters).

References

• https://arxiv.org/abs/0803.0476
• https://www.statworx.com/de/blog/community-detection-with-louvain-and-infomap/