Refactor accounts app into authentication and club apps

- Split the accounts app into new authentication and club apps for better separation of concerns.
- Migrate the custom User, Member, and Family models to the authentication app.
- Introduce Club and ClubMembership models in the club app.
- Refactor Family model to use UUID as the primary key and consolidate family-role relationships into a new FamilyMembership model.
- Update tests, managers, and migrations to align with the new structure.

authentication/apps.py

@@ -0,0 +1,5 @@
+from django.apps import AppConfig
+
+
+class AuthenticationConfig(AppConfig):
+    name = 'authentication'