split the selection panel into one card per kind of selection

src/ui/selection/SelectionNames.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include <QString>
+
+#include "BuildingType.h"
+
+// Display name of a building type for the selection panel's header and count rows
+// (REQ-UI-SELECTION-CARD, REQ-UI-MULTI-SELECTION). The name is derived from the type's
+// config id, so a new building type needs no entry here.
+QString getBuildingTypeName(BuildingType type);