This enables us a fast reference to the entities current chunk instead
of having to look it up by hashmap lookups.
We also store counts by type to further enable other performance optimizations in later patches.
Fires when an Entity decides to start moving to a location.
This is not the same as a move event. This only fires when an entity chooses
to start moving to a location, and allows cancelling that pathfind.
Additionally, only get is supported for now. Unsure if changing target location
is safe to do.
