Loadouts system

This pulls in the new loadouts system.

Features:
* Players can now choose to play as NATO, FIA, AAF or CSAT forces
* New enemy faction: NATO

Regressions:
* Divers disabled. Chaning equipment of players in water is not functional with new loadouts system (for now). Playtesting also showed that players didn't enjoy diver scenarios as much because the SDAR range is so low. Will probably revisit this later.