Document how to use static-ips for workload clusters

Describe the solution you'd like VSphereMachineTemplate and VSphereMachine both seem to support providing static IP adresses. From older issues reported here it seems like a list of IPs could be provided to the VSphereMachineTemplate so all MachineDeployments use one of those IPs until none is left. However there is no documentation on how exactly to do this and at least with the latest vSphere Provider v0.7.9 running on v1alpha3 I wasn't able to create a working configuration.

VSphereMachineTemplate.infrastructure.cluster.x-k8s.io "capi" is invalid: spec.template.spec.network.devices.ipAddrs: Forbidden: cannot be set in templates is returned by clusterctl when trying to set ipAddrs and it's unclear how to edit the YAML generated by clusterctl so machines are deployed using static IPs.

Environment:

• Cluster-api-provider-vsphere version: 0.7.9
• Kubernetes version: 1.21.1
• OS: Ubuntu 20.04.2 LTS