[AVL-19] De-couple the sumo-ego vehicle functionality from the sumo-ai vehicle

[hatfield-c]

Presently, both ego vehicles and sumo vehicles use the same classes in both Unity and Python to control themselves.

According to the Single Responsibility Principle, they should be abstracted into separate classes. There should be a base class which receives control orders from its "control system", and both ego and sumo control paradigms should be placeable as this "control system".