Add "Number of Unique Superchargers Visited" to Locations page

[scissorfighter]

This is just a semi-silly request for those of us who like to try to track how many different superchargers we've been to. The Locations page already has a "Geo Fences" column, listing all geofences, but these could also include non-supercharger locations. I'd like to see a counter at the page top based on the number of geo-fences that contain the word "supercharger" in the name.