Revert citizen train times to A23 values

The significant slowdown in train times, particularly for infantry resulted in an increase in the # of barracks and overall contributed to shifting towards a defensive, turtley gameplay.
Cavalry was already reverted in rP25129.

Reverts parts of D2866/rP24226.

Patch by: ValihrAnt

Reviewed By: wraitii

Differential Revision: https://code.wildfiregames.com/D4033