1. Proposed title of this feature request

Configure API and Ingress VIPs in GCP IPI installation.

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

It would be a good addition to configure API and Ingress VIPs in GCP IPI installation, 

setting them up in the instal-config.yaml file. Something like:

platform:
  gcp:
    apiVIPs:
      - <api_ip>
    ingressVIPs:
      - <wildcard_ip>

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

If a cluster needs to be redeployed, in a disaster scenario for example, the IPs are automatically assigned. This causes that all the networking around the cluster needs to be reconfigured. Assigning the IP would make the recreation much simpler, without any extra configuration in external systems needed .