Simple collisions

Provided an additional, straightforward implementation of the CollisionMap using instance of checks, called `PlayerCollisions`.

Extracted the default collision map as it was into a new class, called `DefaultPlayerInteractionMap`.

The `PlayerCollissions` appraoch is easier to understand, but harder to extend compared to the CollisionInteractionMap

As JPacman is a framework for teaching purposes, it is actually instructive to keep both.