wildfly-operator postgresql example does not work with taskrs-app:18.0

[yersan]

The example does not work with the following image quay.io/wildfly-quickstarts/taskrs-app:18.0

This image does not contain the postgresql-datasource, so we cannot configure it with supplied examples/postgresql/crds/taskrs-app.yaml custom resource definition.

I would suggest to build the S2I image including the following galleon layers: jaxrs-server,postgresql-datasource

I also found a mismatch in the name of the route created for this example, instead of taskrs-app it should be taskrs-app-route

I suggest to include also the complete steps to create the database server and secret, so users don't have to search for the information and allow them to run an example rapidly.

@jmesnil I can improve a bit the example if you want, however, I cannot push the correct image including the missing Galleon layer in quay.io, so if you do that, let me know so I can review and try to improve a bit the example.

[yersan]

@jmesnil The application image to be built must use the following Galleon layers: jaxrs-server,postgresql-datasource,observability