Handle auth_request directive double check

[max-lt]

The auth_request directive sould not be triggered when the auth_jwt one successfully authenticates the request:

• auth_jwt must be executed before auth_request (because it is fastest).
• auth_request must be called only if auth_jwt is disabled or failed to authenticates the request.

This behavior must be optional:

• add a directive to enable it (auth_jwt_options [handle_auth_request]?)