After serveral experiments, it's now known that in the PNC build system it's not possible to get the regstiries downloaded, and thus, we had to add the  -DquarkusRegistryClient=false  option the build-quarkus-app.sh, both for creating the template projects and for adding extensions.

I think this leads us to  the conclusion that we don't need to create the config.yaml

registries:

• registry.quarkus.redhat.com
• registry.quarkus.io
  since we are jut bypassing any registry client interaction