Convert demo to more standard components

[matzew]

Motivation:
Leave as many components as-is and see how far we can get to be able to give the same demo but using purely Knative custom resources

• Source: https://gist.github.com/matzew/77afd1066fdbf75ffb317132f224f8ec
• Subscriber could be normal web servers, like VErt.x or Microprofile