[Gameplay] "Satrapy Tribute" feature for the Persian Throne Hall structure

This adds an upgrade option for the Persian "Apadana" (will be renamed later to "Tachara"), where the player can choose to receive a trickle of a desired resource, like taxes or tribute from their subject peoples. Call this the "Satrapy Tribute" feature.

Patch by: @wowgetoffyourcellphone
Accepted by: @real_tabasco_sauce
Comments by: @chrstgtr, @borg-

Differential Revision: https://code.wildfiregames.com/D5192