Disable artillery towers and bolt towers in-game.
Introduced by rP23094 and rP23160 respectively, these templates were introduced without taking gameplay considerations into account, and players disliked them.
De-activate them from regular play until a better solution can be found.
Test Plan: Check for completeness and correctness. Agree unbuildable is an improvement over brokenness.
Patch by: Nescio
Accepted by: borg-, wraitii
Differential Revision: https://code.wildfiregames.com/D2495