[kubernetes/kubernetes] WIP: kubeadm: deprecate the "node-role.kubernetes.io/master" label / taint (#95382)

DRANK

**What this PR does / why we need it**: please review the separate commits: ``` - Mark the "node-role.kubernetes.io/master" key for labels and taints as deprecated. - During "kubeadm init/join" apply the label "node-role.kubernetes.io/control-plane" to new control-plane nodes, next to the existing "node-role.kubernetes.io/master" label. - During "kubeadm upgrade apply", find all Nodes with the "master" label and also apply the "control-plane" label to them. - During upgrade health-checks collect Nodes labeled both "master" and "control-plane". ``` ``` - Rename the constants.ControlPlane{Taint|Toleraton} to constants.Master{Taint|Toleraton} to manage the transition. - Mark constants.Master{Taint|Toleraton} as deprecated. - Use constants.Master{Taint|Toleraton} instead of constants.ControlPlane{Taint|Toleraton} everywhere. - Introduce constants.ControlPlane{Taint|Toleraton}. - Add constants.ControlPlaneToleraton to the kube-dns / CoreDNS Deployments to make them anticipate the introduction of the "node-role.kubernetes.io/control-plane:NoSchedule" taint (constants.ControlPlaneTaint) on kubeadm control-plane Nodes. ``` **Which issue(s) this PR fixes**: <!-- *Automatically closes linked issue when PR is merged. Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`. _If PR is about `failing-tests or flakes`, please post the related issues/tests in a comment and do not use `Fixes`_* --> xref https://github.com/kubernetes/kubeadm/issues/2200 **Special notes for your reviewer**: NONE **Does this PR introduce a user-facing change?**: <!-- If no, just write "NONE" in the release-note block below. If yes, a release note is required: Enter your extended release note in the block below. If the PR requires additional action from users switching to the new release, include the string "action required". For more information on release notes see: https://git.k8s.io/community/contributors/guide/release-notes.md --> ```release-note ACTION REQUIRED: kubeadm: - The label applied to control-plane nodes "node-role.kubernetes.io/master" is now deprecated and will be removed in a future release. - Introduce a new label "node-role.kubernetes.io/control-plane" that will be applied in parallel to "node-role.kubernetes.io/master" until the removal of the "node-role.kubernetes.io/master" label. - Make "kubeadm upgrade apply" add the "node-role.kubernetes.io/control-plane" label on existing nodes that only have the "node-role.kubernetes.io/master" label during upgrade. - Please adapt your tooling built on top of kubeadm to use "node-role.kubernetes.io/control-plane". - The taint applied to control-plane nodes "node-role.kubernetes.io/master:NoSchedule" is now deprecated and will be removed in a future release. - Apply toleration for a new, future taint "node-role.kubernetes.io/control-plane:NoSchedule" to the kubeadm CoreDNS / kube-dns managed manifests. Note that this taint is not yet applied to kubeadm control-plane nodes. - Please adapt your workloads to tolerate the same future taint preemptively. ``` **Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.**: <!-- This section can be blank if this pull request does not require a release note. When adding links which point to resources within git repositories, like KEPs or supporting documentation, please reference a specific commit and avoid linking directly to the master branch. This ensures that links reference a specific point in time, rather than a document that may change over time. See here for guidance on getting permanent links to files: https://help.github.com/en/articles/getting-permanent-links-to-files Please use the following format for linking documentation: - [KEP]: <link> - [Usage]: <link> - [Other doc]: <link> --> ```docs - [KEP]: http://git.k8s.io/enhancements/keps/sig-cluster-lifecycle/kubeadm/2067-rename-master-label-taint/README.md ```