Document the preservation of Kopf's persistence state in "v1" CRDs

[nolar]

What do these changes do?

Convert CRDs from v1beta1 to v1 API version, and document the unknown field preservation for Kopf's status storage.

Description

Kubernetes 1.16 introduced new changes to custom and built-in resources with stricter schemas and no possibility for arbitrary field storage by default:

• https://kubernetes.io/blog/2019/06/20/crd-structural-schema/

There are workarounds though — via x-kubernetes-preserve-unknown-fields: true.

This PR documents these workarounds and upgrades the framework's CRDs to v1. Legacy CRDs for Kubernetes <= 1.15 are stored nearby (useful when starting in e.g. GKE with default K8s 1.14 and maximum 1.15).

The CRD definition is the only difference. The framework is supposed to work with both versions of CRDs. And the new annotations storage (#331) should solve the root problem "properly" via the code.

Issues/PRs

Issues: #358 #308 #321

Related: #331

Type of changes

• Mostly documentation and examples (no code changes)

Checklist

• Documentation reflects the changes

[zincr]

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✅ Large Commits
✅ Approvals
✅ Specification
✅ Dependency Licensing

[zincr]

🤖 zincr found 1 problem , 0 warnings

❌ Approvals
✅ Large Commits
✅ Specification
✅ Dependency Licensing

Details on how to resolve are provided below

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Approvals

All proposed changes must be reviewed by project maintainers before they can be merged

Not enough people have approved this pull request - please ensure that 1 additional user, who have not contributed to this pull request approve the changes.

• ✅ Approved by PR author @nolar
• ❌ 1 additional approval needed