Destroys a SpawnPool  in PoolManager.Pools including all instances and references as well as the GameObject.

IMPORTANT: This is going to destroy the instances, NOT despawn. Make sure you only do this when performance is not an issue, such as when a level ends or a new level is loaded.

This is just provided for convenience. You can also destroy the GameObject, with the SpawnPool component, directly to achieve the same result as the SpawnPool will detect it is being destroyed and clean up after itself. This is really only here to make it easier when a reference isn't at hand.