Quarkus Non blocking annotation

[franz1981]

https://github.com/rmh78/quarkus-performance/blob/master/demo-quarkus/src/main/java/de/harald/test/demo/WelcomeResource.java should use a NonBlocking annotation in the endpoint because the computed return value is not "async" and the Quarkus ergonomic will handoff it to a blocking thread pool (and back to the event loop), more suitable for blocking operations e.g. hibernate queries.

Both peak throughout and memory usage will change dramatically