Prepare for supporting GL Terminal predictions

[PaulJKim]

Summary of changes

Asana Ticket: Add stop IDs for new GL terminal predictions

According to the Glides team, the places that will start having Glides-based predictions are:

• Boston College
• Cleveland Circle
• Riverside
• Union Square
• Medford/Tufts
• Mattapan

We only have countdown clocks at Riverside, Union Sq, and Medford/Tufts out of this list.

The configuration won't need to change for Medford Tufts or Riverside with the exception of starting to announce boardings.

The Union Sq platforms each serve both directions so they have special platform stop ids that help us tell riders which track a train is predicted to leave from. This is the same setup that we use at most heavy rail terminals.

[github-actions]

Coverage of commit a4b8d02

Summary coverage rate:
  lines......: 75.5% (1926 of 2552 lines)
  functions..: 77.1% (524 of 680 functions)
  branches...: no data found

Files changed coverage rate:
                                                             |Lines       |Functions  |Branches    
  Filename                                                   |Rate     Num|Rate    Num|Rate     Num
  =================================================================================================
  lib/content/utilities.ex                                   |40.5%     74|75.0%     8|    -      0

Download coverage report

[panentheos]

Looks right to me!