Fix mirages (and any other entity that blocks something but not BlockConstruction) blocking foundation construction following rP21597 / D21.
Clean the code by removing the animal hardcoding in the Foundation component and adding a flag DeleteUponConstruction to the Obstruction component.
Have locked gates and upgraded entities equally delete entities when transforming.
Add a workaround for trees inside walls on random maps.
Reviewed by: temple
Differential Revision: https://code.wildfiregames.com/D1415
Refs #4268