Add support for new image_name format in `cluster-<provider>` apps.

[ericgraf]

Newly built CAPI images will now have a new image naming format. The image name format looks like: flatcar-<flatcar channel>-<flatcar release>-kube-v<k8s version>-<build suffix> -> flatcar-stable-3815.2.2-kube-v1.26.15-gs .

If desired , provider teams can manually build old releases using the new naming format. How to instructions.

If the cluster charts need to use any newly built images, they will need to add support for the new format.

Here is a list of Cluster- apps that need support:

• [ ] cluster-azure
• [ ] cluster-aws
• [ ] cluster-vsphere
• [ ] cluster-eks
• [ ] cluster-cloud-director

[nprokopic]

The image name format looks like: flatcar-<flatcar channel>-<flatcar release>-kube-v<k8s version>-<build suffix> -> flatcar-stable-3815.2.2-kube-v1.26.15-gs

Is this exactly the same for all providers?

[paurosello]

@nprokopic this is done already right?