D1761/rP22984 enabled workshops for all civilizations and removed siege engines and technologies from the fortresses, D2532/rP23746 made champion cavalry trainable at the stable. This patch:
* enables the stable for all civilizations;
* removes cavalry from all barracks;
* removes cavalry speed technologies from corral;
* removes champion cavalry and chariots from all fortresses;
* makes champion chariots trainable at the stable;
* deletes the now obsolete `{civ}_champion_cavalry_barracks.xml` templates;
* changed the costs of barracks and stable:
* barracks and stable build time from 150 to 120;
* barracks cost changed to 150 wood, 100 stone, except for brit, gaul, maur, which cost 250 wood, instead of 300+0, 150+150, or 100+200;
* stable cost from 300 to 250 wood.