Prepare models for new chat feature

Signed-off-by: Emmy D'Anello <emmy.danello@animath.fr>

chat/apps.py

@@ -0,0 +1,9 @@
+# Copyright (C) 2024 by Animath
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from django.apps import AppConfig
+
+
+class ChatConfig(AppConfig):
+    default_auto_field = "django.db.models.BigAutoField"
+    name = "chat"