kubeadm-reset: add means to clear the ClusterStatus

[neolit123]

What this PR does / why we need it:

Add ResetClusterStatusForNode() that clears a certain
control-plane node's APIEndpoint from the ClusterStatus
key in the kubeadm ConfigMap on "kubeadm reset".

based on work by @Klaven in this PR:
#72886

Which issue(s) this PR fixes:

Fixes kubernetes/kubeadm#1312

Special notes for your reviewer:

this patch is tested on a multi-CP cluster.

we might want to approach this withConfigMap(...).Patch() instead, eventually.
i didn't have time to test Patch() today.

Does this PR introduce a user-facing change?:

kubeadm: when calling "reset" on a control-plane node, remove the APIEndpoint information for this node from the ClusterStatus in the kubeadm ConfigMap.

/assign @timothysc @fabriziopandini @rosti
cc @Klaven
cc @kubernetes/sig-cluster-lifecycle
/priority critical-urgent
/kind bug
/kind cleanup

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: neolit123

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[rosti]

Thanks @neolit123 and @Klaven!
We still need tests for ResetClusterStatusForNode, but lets have this as is.

/lgtm