[rnd] evaluate possibility, requirements and limitations for implementing IPAM for GCP

[BROngineer]

// TBD

[kylewuolle]

Developed a prototype that simply allows an IP Address to be specified for worker and control plane nodes in GCP. The prototype involved hardcoding the ip addresses in the gcpmachinetemplate-worker.yaml and gcpmachinetemplate-controlplane.yaml files for simplicity. It is fairly trivial to have those provided via the IPAM infrastructure in place already. In order to implement IPAM for GCP we will require either a patched build of the GCP CAPI Provider or the following PR to be merged upstream : kubernetes-sigs/cluster-api-provider-gcp#1499.

edit PR kubernetes-sigs/cluster-api-provider-gcp#1499 isn't required and instead we will need kubernetes-sigs/cluster-api-provider-gcp#1314