1. Proposed title of this feature request

Allow ARO to enable setting V4InternalSubnets during install process to avoid network CIDR conflict.

2. What is the nature and description of the request?

The default CNI is OVNKubernetes for 4.11 and above.  OVN-K uses some default CIDR ranges for `InternalTransitSwitchSubnet` and `internalJoinSubnet`.  OVN-Kubernetes reserves these IP address ranges. These subnets cannot be overlapped with any other internal or external network. Therefore this request is to allow customization of these ranges upon ARO cluster install.

https://docs.openshift.com/container-platform/4.16/rest_api/operator_apis/network-operator-openshift-io-v1.html#spec-defaultnetwork-ovnkubernetesconfig-ipv4

It is able to be configured after cluster install: https://docs.openshift.com/container-platform/4.16/networking/ovn_kubernetes_network_provider/configure-ovn-kubernetes-subnets.html

In OCP one can configure the values at install time.

3. Why does the customer need this? (List the business requirements here)

Customers may have overlap with the defaults on their network.

4. List any affected packages or components.

OVN-Kubernetes