Improve Kubernetes CRDs

[mloiseleur]

What does this PR do?

This PR is fixing Kubernetes CRD on the following points:

• Provide example value from doc.traefik.io in the CRD
• Provide default value in the CRD
• Provide validation definition to check expected content: Enum, ~~UniqueItems~~, Pattern, Minimum or CEL validation expression when appropriate
• Provide printable columns for IngressRoute, IngressRouteTCP, IngressRouteUDP, TLSOption and ServersTransport
• Improve description with deprecated when the field is not documented

Motivation

Improve CRD help Traefik Proxy Kubernetes user when submitting or editing CR.

More

• [ ] Added/updated tests
• [x] Added/updated documentation

Additional Notes

Documentation for CRD validation with kubebuilder is here. It's hard to tell all possible case, so I rely on current integration test suite. I'll need guidance if some new tests (related to CEL validation expression, for instance) needs to be written.

[nmengin]

Hello @mloiseleur,

Thank you for your contribution.

We've kept the status to "need-triage" to allow us to check the PR and ensure we agree with the use case before moving forward. We'll keep you updated once the analysis is done.

[mloiseleur]

This PR has been superseded by #11310 and #11311