Make use of overall seconds spent in video (relative to FPS)
Prepare two new fields for realtime api (api/realtime/occupancy):
last_time_relative - Time spent since video has been started. It is relative to FPS
last_time_registered - Last time (spent since software has been started) when vehicle has been registered is zone (via crossing virtual line or appearing in zone) calculated. Measure in seconds.
api/realtime/occupancy):