Switch to controller-gen for CRD generation and update CRD to apiextentions v1

[k0da]

Description

Fixes #2000

Checklist

• Unit tests updated
• End user documentation updated

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[njuettner]

Nice 👍🏻 , thanks for updating apiextension to v1, I'm fine merging it. This should work with >= v1.16.

/cc @Raffo

[Raffo]

I'm fine with this change.

[k0da]

/assign @njuettner

[Raffo]

/approve
/lgtm

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: k0da, Raffo

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