Tweak how default config is defined for auth API views

so it may be more easily extended

tailbone/api/auth.py

@@ -128,6 +128,10 @@ class AuthenticationView(APIView):
 
     @classmethod
     def defaults(cls, config):
+        cls._auth_defaults(config)
+
+    @classmethod
+    def _auth_defaults(cls, config):
 
         # session
         config.add_route('api.session', '/session', request_method='GET')