Vehicle Command Gate

[maxime-clem]

It was decided that a Vehicle Command Gate will be added to Autoware. Assuming multiple modules are output control commands, this gate will allow selecting which control command is sent to the VehicleInterface to control the vehicle.

The remaining discussion point concerns the implementation of this adapter and whether it should be a functionality of the VehicleInterface node, or an independent node between the controllers and the VehicleInterface.

[JWhitleyWork]

I was convinced during the last call that I was on that it doesn't really matter that much. I prefer it to be part of the VehicleInterface for convenience and so the information about where the commands are coming from is available to other parts of be VehicleInterface but it really doesn't matter all that much.