Additional trucking

Now mission truckers can be performed on any car with a trailer (tractor + trailer, truck + trailer, tractor + truck, passenger car + trailer, + wrecker towed cars, and so on). Works as a standard for cars and trailers, and for an additional set (if you have the plugin Alexander Koryakina "GTA SA Vehicle Special Abilities Editor" and additional cars registered in it). To start the mission, we must stay in the car with a trailer on the red area near the base of truckers. The script only works when the player does not fulfill the mission and open all of the city.