Slow loading after implementing oil well locations

[perfectly-preserved-pie]

There is significantly reduced loading speed on the website now that I've implemented oil well locations (a 5s delay to render the page!) in #176. I suspect it's due to the size of the GeoJSON file which is about 22MB.

I will need to look into lazy loading and perhaps removing unused feature properties as well as filtering out any oil wells that aren't in LA Country.