WIP add storage migration automation for Azure

[mihiragrawal]

After Upgrading the k8s version to 1.26, we have encountered volume attachment failures due to node affinity label deprecation on Azure clusters. This happens on both the Seed cluster and User clusters. This is due to the label deprecations by the k8s community. And currently, there is no straightforward way to fix that. So we have come up with automation to solve this issue.

Here is the upstream issue, which was closed without any solution.

To Reproduce:

• Create a k8s cluster on Azure with in-tree CSI. The cluster k8s version should be older than v1.21.
• Deploy workload with volume usage.
• Move to external CSI driver.
• Upgrade k8s cluster to 1.26

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

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[toschneck]

@mihiragrawal any news on this? Please add it also to the README.md

[toschneck]

@mihiragrawal can you check what is the state