Expose clustering of points

[Zebreu]

Today we're clustering points according to their pairwise distance to make sure some neighbors in densely packed areas aren't split across routes. However, this is not exposed in our configuration and some users would probably want to be able to adjust how clustered the points are and ideally we'd provide a view of what those clusters are in the GUI

[Zebreu]

Done in the latest PR via a global config field, clustering_radius