[SDL 0262] New vehicle data SeatOccupancy

[theresalech]

Proposal: New vehicle data SeatOccupancy

This proposal is to add new vehicle data SeatOccupancy to know if a vehicle seat is occupied and belted.

Review: smartdevicelink/sdl_evolution#870

Steering Committee Decision:

The Steering Committee voted to accept this proposal with the following revision: update SeatOccupancy parameter description to "Seat status array containing the location and whether the seats are belted."

The proposal .md file was updated to reflect these revisions on 12/4/19.