Just another use case to test. This is supposed to be the desired
mode for core-middleware, so we should at least have this tested as
chances are high that admins want to align on the redis deployment.

UI Middleware instance for prefix deployments was not restarted, so deployment could be "old".
Online help was broken for prefix deployments, adjusted virtualservice to match deployment

describe a little better what this service is supposed to do and how
it plays along the other parts of the stack.

just point manifest service instance to appsuite-stack release created for preview apps.
Needs some custom k8s resources (Ingress).