When deploying Knative Serving to OpenShift 4, we should default the `istio.sidecar.includeOutboundIPRanges` in serving's config-network to the address space of the OpenShift cluster.

This is available via a CRD in Openshift 4 as `status.serviceNetwork`:

`oc get network cluster`

Note that there could be more than one serviceNetworks defined there. We could cheat for now and assume only one or cheat even more and assume only `172.30.0.0/16`. But, that's cheating.

Without this set, any calls to external services from within Knative-deployed services will fail unless you create a specific egress rule allowing it in Istio.

Acceptance Criteria:

• (maybe) The install script sets the value automatically
• The new operator sets the value automatically