AMQP-429: Change `@SendTo` logic to `Address`

JIRA: https://jira.spring.io/browse/AMQP-429

Since `@SendTo` can apply only `String` values, but from other side `Address` can parse that `String`,
there is no stops to use `Address` object as a `replyToAddress`.
Now to send a result of `@RabbitListener` method to some specific `replyTo` you can specify it like this:
```
@RabbitListener(queues = "test.sendTo")
@SendTo("direct:///test.sendTo.reply")
public String capitalizeAndSendTo(String foo) {
	return foo.toUpperCase();
}
```

* Add integration test
* In addition remove redundant `@RabbitListener.responseRoutingKey()`
Agreed - just get rid of the type in `Address` and your semantics look good to me.