Enable clustering for bikeshare hubs

[barbeau]

Summary:

We currently have clustering enabled for bikeshare floating bikes, but not for hubs. This is because there used to be very few hubs (2-3) on USF campus. However, with the change from USF Share-A-Bull to management under Coast Bikeshare, they are adding a lot more hubs on campus (and we now have actual physical hubs now in Downtown Tampa and St. Pete, which I assume will also show up in the app).

So, we need to enable marker clustering for bikeshare hubs as well

Steps to reproduce:

Go to the USF Maps Bikeshare layer:
https://maps.usf.edu/#layers/bike_stations

Expected behavior:

Hubs should cluster when I zoom in and out

Observed behavior:

No clustering happens for hubs