Fixed AI missile silo building behaviour

Changes:
- Further improvements on resource management for the AI, which should increase difficulty and late game capability
- AI now builds more farms depending on the city level
- AI builds more artillery
- Resource boost calculation has been adjusted to especially help the AI with their midgame
- AI now needs a bigger unit amount advantage before activating their military

Fixes:
- Fixed a calculation that could result in a division by 0, which would crash and stop the script for the remainder of the match

(Hopefully) made the AI more capable in regards to military in the early game

Fundamental changes to caravan wealth correction

- Added new AI army compositions that hopefully spice up the game a bit
- Fixed a bug with the army composition system that lead to the AI building less units than they were supposed to
- Now forces the AI to buy really cheap resources when they can afford it

Fixes and changes:
- AIs start with a smaller resource boost and should spend more on units over the course of the game
- AIs won't build Priests anymore as they weren't using them
- AIs should now upgrade their scouts properly

AIs now properly build:
- Modern resource buildings in Information Age
- AA defences from Industrial Age onward
- Conventional Missiles

This update also contains compatibility with the new future units of the corresponding update of the main mod.

- AI now builds a lot more towers and hopefully units to counter enemy attacks, especially in early game

Performance improvements