Move apps in main directory

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

registration/auth.py

@@ -0,0 +1,17 @@
+# Copyright (C) 2020 by Animath
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from cas_server.auth import DjangoAuthUser  # pragma: no cover
+
+
+class CustomAuthUser(DjangoAuthUser):  # pragma: no cover
+    """
+    Override Django Auth User model to define a custom Matrix username.
+    """
+
+    def attributs(self):
+        d = super().attributs()
+        if self.user:
+            d["matrix_username"] = self.user.registration.matrix_username
+            d["display_name"] = str(self.user.registration)
+        return d