Include Occupancy status (GTFS-RT v2) in TransitClock

[wkulesza]

Following adoption of Occupancy status in GTRS-RT v2 (details here: (https://gtfs.org/reference/realtime/v2/#enum-occupancystatus it would be important to include this in TransitClock for a number of reasons:

• real-time information on map (per each vehicle visible on map)
• historical information in reports

Both would significantly (especially during panedmic times) help dispatchers react both instantly and planners react more efficient in deploying suitable vehicles based on the data.

Since the data could come from APC or other external systems (that would i.e. include vehicle id and enum value of occupancy status), it would need to be stored in TC database and be included in the produced vehicle_positions in GTFS-RT (there are already consumers of that data, including Google Maps and OneBusAway).

[sheldonabrown]

https://github.com/TheTransitClock/transitime/pull/235

Added OccupancyStatus support per Camsys's repo

Its not complete per the above, but adds significant support for OccupancyStatus.

[Raven888888]

@sheldonabrown @scrudden Can we merge this feature? What is still not complete?