move storage classes into server folder and fix error in localStorage when winner_snake is none

server/storage/StorageLoader.py

@@ -0,0 +1,7 @@
+
+class StorageLoader:
+  @classmethod
+  def build(self, selected_storage:str):
+    storage_module = __import__(f'server.storage.{selected_storage}', fromlist=[selected_storage])
+    storage_class = getattr(storage_module, selected_storage)
+    return storage_class