[Feature]: Add UI to control rebel AI loadout system

[jaj22]

There's been a persistent requests for an AI loadout specification system. Using player loadouts isn't acceptable due to balance & exploit problems, so the simplest solution is to add a UI with class-based limits. For example, for grenadiers, the primary weapon box would only show grenade launchers, and the secondaries would be disabled. Ammunition would still be automatic, although we could give approx quantity options.