add h3 hexbins to command line hexbin option

[burritojustice]

trafficstars

Add h3 hexbins as an option to the command line hexbins, which are currently degree-based.

https://github.com/uber/h3-js

This would assist the visualization of large, dense datasets where the response time is too great for the h3 hexbins dynamically generated by Data Hub's dynamic clustering. Also, higher resolution hexbins (and especially their centroids) viewed at lower map zoom levels would be a useful visualization technique for dense and / or irregularly distributed data sets.