Moves unit to the first available seat in a vehicle.
The order of priorities is the same order used in squad command when you order subordinates to get in vehicle to any position, and is the same order used in Zeus when you drag units to a vehicle.
Seat assignment seems to use the following priority logic: driver (moveInDriver) -> commander turret (moveInCommander) -> gunner turret (moveInGunner) -> remaining turrets (moveInTurret) -> cargo (moveInCargo).
NOTE: This command will move player into the locked vehicle or seat just as well.
Returns true (since game version 1.27) if the command succesfully moves the given object.