rP22257 introduced new cattle templates. Unfortunately, they contained mistakes. This patch corrects them:
* removes unnecessary <Civ>gaia</Civ>, because all units and gaia objects already have this by default
* add <GenericName>
* correct <SpecificName> capitalization: in scientific names //Genus// is always capitalized, //species// and //subspecies// never.
* moved shared parent: `template_unit_fauna_hunt_passive_cattle.xml` → `template_unit_fauna_herd_domestic_cattle.xml`
* merged the `*_trainable.xml` template values into the shared parent
* added European cow to gaul corral and Sanga cattle to kush corral so they can get used
Also removed duplication from the new horse templates introduced in rP22260.