Adding the Mattapan trolley

[devinmatte]

Motivation

Adds the Mattapan Trolley to the dashboard

We already have the data for it and the performance API supports it

Need to make sure some of the stops are correct, whoever reviews please sanity check stations.json stop maps

Changes

Adds the Mattapan Trolley to the dashboard using Subway presets and a few disabled pages

Testing Instructions

Test on beta, paying attention to weirdness