Currently we have no API "multi-zone" primitives nor first class support for it as a concept. A multi-zone cluster needs to be set up "by hand".

E.g In AWS the cloud provider config file will only get a zone if `hcp.Spec.Platform.AWS.NodePoolDefaults.Zone` is set. A nodePool is tied to a particular zone.

We might want to consider enable support for a multi-zone experience by providing some out of the box automation.

E.g when in multi-zone mode a nodePool is automatically creating for each zone when requesting compute capacity.