Implement config-driven unlock groups so that multiple things can be unlocked at once (including buildings)

src/lib/config/GameConfig.h

@@ -6,6 +6,7 @@
 #include "ShipsConfig.h"
 #include "StationsConfig.h"
 #include "ModulesConfig.h"
+#include "UnlocksConfig.h"
 #include "ThreatCostCalculator.h"
 
 // Aggregate of all simulation config files. Loaded at startup and reloaded
@@ -18,5 +19,6 @@ struct GameConfig
     ShipsConfig ships;
     StationsConfig stations;
     ModulesConfig modules;
+    UnlocksConfig unlocks;
     ThreatCostTable threatCosts;
 };