usabart: Bring in usaebart and OAK shuttle

[Nagamasa]

BART is currently split into 3 different systems:

• the main wide-gauge 5-line service
• eBART, standard guage DMU extension of the Yellow line
• OAK Connector AGT shuttle to OAK/li]
  

All of these are mapped as equals on the BART System Map: https://www.bart.gov/system-map, I don't think we should be splitting it up here into separate systems based on the infrastructure provided. Proposal is to consolidate usaebart into usabart and move OAK Connector out of usaair into usabart.