Area Cost- for "difficult to walk" areas

[tzachshabtay]

Inspiration from Construct 2's path finder: https://www.scirra.com/manual/154/pathfinding

We might want to have areas that the character prefers not to walk in, unless it's a really big shortcut. This might be a rough terrain, or an area with an uninviting character etc. We can add an area cost component that will be used by the path finder for that.

Also, for rough terrains, we might be able to add a walk speed component for specific areas to also make the walk speed slower on them.