Currently:
* `units/cart_cavalry_swordsman_gaul_*` templates use `units/gauls/cavalry_swordsman_*` actors
* `units/cart_infantry_swordsman_gaul_*` templates use `units/gauls/infantry_swordsman_*` actors
* `units/cart_infantry_javelinist_iber_*` templates use `units/iberians/infantry_javelinist_*` actors
* `units/cart_infantry_slinger_iber_*` templates use `units/iberians/infantry_slinger_*` actors
However, the `units/cart_cavalry_swordsman_iber_* templates use `units/carthaginians/cavalry_swordsman_*` actors. This patch moves those to the `iberians/` folder for consistency and to avoid potential, future duplication.