Support for disabled Load Balancer #1429
Description
/kind feature
Describe the solution you'd like
Cluster API has contracts to support externally managed Control Planes and it's widely used by several other CAPI implementations: OpenStack, AWS, Azure, and many others.
In a such scenario, the Control Plane would be backed by a third provider (Control Plane Provider, e.g.: Kamaji which is responsible for providing the Control Plane Load Balancer).
When the Load Balancer is disabled, the GCP Cluster API provider should wait for a Load Balancer address, without taking for granted the LB must be always generated by itself.
Anything else you would like to add:
This is an effort to support Hosted Control Planes also in the Google Cloud Platform, and I'm open to raising a related PR to get this done.