Change validators to use the validator_context

Change InstanceKeys to take a namedtuple for context

util/config/validators/validate_apptokenauth.py

@@ -4,7 +4,9 @@ class AppTokenAuthValidator(BaseValidator):
   name = "apptoken-auth"
 
   @classmethod
-  def validate(cls, config, user, user_password, app):
+  def validate(cls, validator_context):
+    config = validator_context.config
+
     if config.get('AUTHENTICATION_TYPE', 'Database') != 'AppToken':
       return