✨ clusterctl: Add public function to create new CRD migrator

[alexander-demicev]

What this PR does / why we need it:

Add public function to create new CRD migrator, we would like to reuse the code in CAPI Operator helm chart hook to help migrate CRDs if needed.

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 #

[killianmuldoon]

/area clusterctl

[fabriziopandini]

/lgtm
/approve

Just a reminder that for everything below clusterctl

When this package is used as a library, we do not currently provide any compatibility guarantees. We will make reasonable efforts to follow a typical deprecation period prior to removal, but breaking changes can happen when necessary.

Also, worth to add that what we support is a minimal CRD migrator specifically designed according to clusterctl requirements (which are the same of the CAPI operator). Folks looking for more advanced CRD migration capabilities should look at https://github.com/kubernetes-sigs/kube-storage-version-migrator or similar projects

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: c0d471b4a5053f852198a439c325765b0f628562

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fabriziopandini

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