Add vehicles (dinosaurs & golf carts) WIP

So this is the start of adding all the vehicles in the game that you see in the end boss against Cornelius. So far you can walk around as Abed's dinosaur in castle-hawkthorne-throne or drive the golf carts in greendale-exterior.

Indentation is a little wonky. I'll fix that later.

I was thinking of using the holdable code in player.lua or doing something similar but not quite sure.