Fix delegation usage in ResumingRouter

[famarting]

I found a bug with vertx-http, in a case like this

    router.post("/hi/bug")
    	    .consumes("application/json")
	    .handler(BodyHandler.create())
            .handler(rc -> rc.response().end("Hi from router"));

my requests was getting stuck and never returned.
After further investigation I found that the class ResumingRouter https://github.com/quarkusio/quarkus/blob/master/extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/ResumingRouter.java wasn't properly implemented and after the call to consumes(... the underliying router was returned instead of the ResumingRouter, this lead into the unexpected behaviour I described above but many other things could be affected.

I have a reproducer for this error here https://github.com/famartinrh/quarkus-with-vertx-web
It can be easily tested running
curl -v -H "Content-Type:application/json" -X POST localhost:8080/hi/bug -d "hello world"

This PR fixes the incorrected implementation of the delegation in the class ResumingRouter and adds some modifications to related tests to cover the usecase

Special thanks to my mate @juazugas for helping me with the troubleshooting