Toggle light nodes and full nodes separately

[xaur]

On the Nodes chart the full nodes (labeled as "reachable nodes") line is almost flat because of the scale difference with regular nodes. I'd like to turn off the regular nodes to better see the dynamic of reachable nodes.

I assume this repository is what is deployed at https://analytics.planetdecred.org/nodes , please let me know if I should post in another repo.