Remote car control (mod) + remote car door open/close

Not exactly finished, but already working system for remotely driving a car.
Adds a controller item (made available with a mod) that allows access to all car control functions like honking, driving around (will skid a lot), displaying car stats on UI and cruise control.

Adds a minor function to all cars: remotely open doors. Currently all doors, but could easily be turned into a part attachable to doors. This is the only function that is visible to everyone - not just those who use the mod and the controller.

Currently works under the assumption that all car controls are relatively high-tech. Could be easily split into high-tech for good stuff and low-tech controls for low end. Or even into human-controllable controls and remote ones, but that would make the whole thing much less fun (only military really has a reason to use remote vehicles).

There are some issues, like remotely driving a car while sitting in it (will throw the player around and probably outside the car) and clunky menus (look_around used to pick a target), but the whole thing works already.