UX improvements: Prune Clustering and Match colour of cluster circles to match dots

[kidwellj]

[kidwellj]

Let's pivot on this and switch to using PruneCluster's categories feature.

[danhillcode]

Closing this issue as it is the same as the icon issue.

[kidwellj]

Still need to resolve issues with dots not displaying custom icons / colours to match for UX across legends and bars.

[kidwellj]

Note relationship to #10