Map integration

[allthesignals]

BostonGreenMap already has a great map built, and we'd like to integrate it into the photo-based design.

Currently, a Leaflet map (of London) is built into the view, but none of the great features from the previous map are built in. We'd like to start with the individual park view, showing:

1. Park's geometry
2. Park activities

Currently, there's a static topojson of all the parks in /parks. The old map filtered this topojson file. This could work for this iteration as well.