Allow usage of "update_effects" in basic "unit" prototype

[CPU_BlackHeart]

TL;DR

Allow usage of "update_effects" in basic "unit" prototype.

What?

Allow usage of the "update_effects" API seen in the demolisher segment to be extended to basic units.

Why?

This would allow in greater variety and options in creating enemy units as it would largely allow a modder to create entities that can passively affect their environment without needed to be on an attack, which allows them to be deterrents or obstacles outside of pollution-based necessities. It would also be ideal to allow an option to have the unit be constantly "enraged" so that it will attack anything in its vision range not on the same force as itself regardless of military priority or otherwise.