A pill can be taken (key 'E', currently in Player.gd for testing) to
increase the level up to the max level (currently 6).
The drugged level gradually decreases down to the min level
(currently 0).
The ground needs to be a PhysicsBody for the collision to work.
Also added colliders to the boxes to further test collision.
The collision seems to have caused some issues with the Meldewesen
pathfinding - I think I know what's wrong, will fix soon.
