extract the production rules as free functions over config and building

src/test/BuildingTest.cpp

@@ -1,5 +1,6 @@
 #include "catch.hpp"
 #include "FactoryQueries.h"
+#include "ProductionRules.h"
 
 #include <map>
 #include <random>
@@ -1562,7 +1563,7 @@ TEST_CASE("BuildingSystem: getProductionStatus classifies production state", "[b
     }
     REQUIRE_FALSE(shipId.empty());
 
-    const auto statusOf = [&f](const Building& b) { return f.bs.getProductionStatus(b); };
+    const auto statusOf = [&f](const Building& b) { return getProductionStatus(f.cfg, b); };
 
     SECTION("non-production buildings show no status light")
     {