Let's continue the work in https://issues.redhat.com/browse/SRVKS-1090 and document the contents user can change either in his own cm or in the default kourier-boostrap cm.

We should have some documentation of what users can change in default cm https://github.com/openshift-knative/serverless-operator/blob/main/openshift-knative-operator/cmd/operator/kodata/ingress/1.11/kourier/1-net-kourier.yaml#L51-L146

eg. how can they have access to the admin interface of envoy.