As pointed out at https://code.wildfiregames.com/D1351#55435 and the subsequent post, the `gather_animals_stockbreeding.json` technology is a must-have for everyone who intends to gather food from batch-training animals from corrals (and useless for everyone else), therefore it's better to simply deprecate the technology and reduce the base time cost of domestic animals.
D3301/rP24527 changed the costs, time, health, and food values of domestic animals.
This patch:
* replaces the −50% domestic animal training time with −0.1 corral batch training time;
* renames the technology file accordingly;
* changes the corral's default <BatchTimeModifier> from 0.7 to 0.8 (same as barracks or stable).