[Add Map] USA coop challenge

### Map Name

COOP VS 3 USA Generals Challenge

### Map Kind

Cooperative Challenge

### Author

mah_boi, Camarade Lenin 343, Dun淼咕

### Author Contact

https://www.moddb.com/members/sxandun

### Download Link

https://www.moddb.com/games/cc-generals-zero-hour/addons/gzh-usa-co-op-challenge-rebalanced