This patch:
* `<Civ>gaia</Civ>` is set only once, in `template_unit_fauna.xml`, rather than repeatedly in various templates.
* icons, names, and visualactors do not belong in the shared `template_*` files and are moved to the appropiate children
* generic and specific names were applied inconsistently and often absent. This patch standardizes the scheme that was already present in some: e.g.: `fauna_crocodile.xml`:
<SpecificName>Crocodylus niloticus</SpecificName>
<GenericName>Nile Crocodile</GenericName>
* corrected the muskox to `hunt_skittish`, because it's not a domesticated species
* cleared up the lioness template, which was mostly identical to the lion.
Not done here, because it belongs in separate patch(es):
* `gaia/fauna_arctic_wolf.xml` should be renamed to `gaia/fauna_wolf_arctic.xml`; cf. `gaia/fauna_fox_arctic.xml`
* `gaia/fauna_mastiff.xml` and `gaia/fauna_wolfhound.xml` should be renamed to `gaia/fauna_dog_mastiff.xml` and fauna_dog_wolfhound.xml`, respectively
* `gaia/fauna_pony.xml` should be renamed to `gaia/fauna_horse_pony.xml`, because it has <Entity parent="gaia/fauna_horse">
* `fauna_fish.xml`, `fauna_fish_tilapia.xml`, `fauna_fish_tuna.xml` are duplicates, identical in all except name.