move ecs related code to own folder

src/lib/ecs/component/SalvageBehaviorComponent.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <optional>
+
+#include <QVector2D>
+
+#include "BuildingId.h"
+
+struct SalvageBehaviorComponent
+{
+    std::optional<QVector2D> scrapTarget;
+    BuildingId deliveryBay;  // kInvalidBuildingId until assigned at a salvage bay
+};