Enable closing map

engine/src/main/java/com/bartlomiejpluta/base/engine/context/model/DefaultContext.java

@@ -88,12 +88,20 @@ public class DefaultContext implements Context {
    @SneakyThrows
    @Override
    public void openMap(@NonNull String mapUid) {
+      log.info("Opening map with UID: [{}]", mapUid);
       map = mapManager.loadObject(mapUid);
       mapHandler = mapManager.loadHandler(this, mapUid);
 
       mapHandler.onOpen(this, map);
    }
 
+   @Override
+   public void closeMap() {
+      log.info("Closing map");
+      map = null;
+      mapHandler = null;
+   }
+
    @Override
    public Entity createEntity(@NonNull String entitySetUid) {
       log.info("Creating new entity with UID: [{}]", entitySetUid);