add license everywhere

antarest/study/storage/abstract_storage_service.py

@@ -1,3 +1,15 @@
+# Copyright (c) 2024, RTE (https://www.rte-france.com)
+#
+# See AUTHORS.txt
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This file is part of the Antares project.
+
 import json
 import logging
 import shutil