Military Camp improvement

Adds an improvement, available for all civilizations, buildable by melee and anti-cavalry units. Military camp is unlocked at Military Tradition civic. It gives your units +2 defense strength, grants fortification, and when your wounded units enter the tile, they instantly heal slightly . Provides +1 production . Comes in 3 variations (ancient-renaissance, industrial, modern). All melee and anti-cavalry units receive a charge to build it, for game balance, they can't harvest nor remove resources, but they can repair tiles. Compatible with S&T, 6T Units. Special thanks to Sailor Cat for providing the code and overall help in development, make sure to check out Watchtower by Sailor Cat. Steam link (detailed description): https://steamcommunity.com/sharedfiles/filedetails/?id=2878166834