Proposed title of this feature request
Support for MachineSet with additional empty disk definition on GCP

What is the nature and description of the request?

• The GCP providerSpec MachineSet section supports the definition of multiple disks.
• if the disk definition does not contain an `image` field we fallback to the project-level default image, see here
• Right now in order to define a MachineSet with additional empty disks we are forced to link the additional disk to an empty image (an image on GCP image storage has a cost)
• As per GCP API doc it is possible to create a VM instance with an additional emtpy disk
• The request of this RFE is to support empty additional disks without the need to link the disk to an image.

Why does the customer need this?

• At this moment creating MachineSets with empty additional disks is cumbersome and requires an empty image (with additional costs)

List any affected packages or components

• machine operator