Hello, guys!
OK, I've changed my mind and here is my opinion:
* `register-default-converters` with `false` by default
* if there is no `message-converters` default ones should be registered
* if `register-default-converters=true` place default convrters in the end of the result list

With that solution we have backward compatibility as it is now, and with `true` we get a required logic.
And there is no need to provide other `*-converters` attributes and have a logic in the parser.