rP8995 (#563) introduced an `ANIMAL`-state from a separate `AnimalAI`-component.
However, why would we need such a separate state? Maybe we want GAIA human units that linger and roam (city-building mods) or we want animals to behave like humans.
This patch therefore removes that state and brings the `ROAMING` and `FEEDING` (could be renamed to e.g. `LINGERING`) under the `INDIVIDUAL.IDLE`-state.