[feautre] Make ClusterConfiguration variable

[chifu1234]

Currently there is no option the handle any special configuration for the cluster (for example to enable oidc).
By making ClusterConfiguration variable you can setup the kubernetes cluster as you like.

Proposal:
1.) Handling ClusterConfiguration with https://pkg.go.dev/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm#ClusterConfiguration struct not as string
2.) Update Object CLusterConfiguraiton with user input from kubicctl.conf key ClusterConfiguration
3.) Update Object ClusterConfiguration with

kubic-control/pkg/kubeadm/initMaster.go

Line 251 in b2ce1e7

_, err = f.WriteString("apiVersion: kubeadm.k8s.io/v1beta2\nkind: ClusterConfiguration\nkubernetesVersion: " + kubernetes_version + "\ncontrolPlaneEndpoint: \"" + in.MultiMaster + ":6443\"\n")

Multimaster
4.) Write Object ´/var/lib/kubic-control/clusterconfiguration.yaml`
5.) update kubeadm args with new location

If you like I can implement my proposal and create a mr?

[thkukuk]

I'm currently busy with other things and have no time for kubic-control, but Patches are always welcome.