Support Backup offerings for CKS Cluster deployment

### The required feature described as a wish

As a User/Admin/Operator I would like to ,associated a backup offering to be associated with a cks cluster .

Currently, there is no way to associate a Backup offering during CKS deployment

https://cloudstack.apache.org/api/apidocs-4.22/apis/createKubernetesCluster.html

Associating a backup offering is only possible when virtual machine is deployed from the ui api

https://cloudstack.apache.org/api/apidocs-4.22/apis/assignVirtualMachineToBackupOffering.html
https://cloudstack.apache.org/api/apidocs-4.22/apis/removeVirtualMachineFromBackupOffering.html

Currently user has to manually associate cks-instance (control and worker node ) to a backup offering

Also, we can take a look to support velero as a backup provider for kubernetes cluster

https://velero.io/

Currently hyperscalers support kubernetes backup offering

https://docs.aws.amazon.com/eks/latest/userguide/integration-backup.html
https://learn.microsoft.com/en-us/azure/backup/azure-kubernetes-service-backup-overview
https://docs.cloud.google.com/kubernetes-engine/docs/add-on/backup-for-gke/concepts/backup-for-gke

從 issue 中參照的 createKubernetesCluster API，以及 assignVirtualMachineToBackupOffering 和 removeVirtualMachineFromBackupOffering API 開始。確認在 CKS 部署期間應如何選取 backup offering，以及 Velero 是否在範圍內；完成後，control 執行個體和 worker 執行個體應能在不需手動關聯的情況下取得要求的 backup offering。

由索引模型根據 Issue 內容生成。