UX: additionalPrinterColumns for PlatformCredentialsSet

[hjacobs]

Adding additionalPrinterColumns makes kubectl and kube-web-view much more useful:

Sadly the CRD JSONPath only supports simple expression, i.e. there is no way to show the number of clients/tokens (would require some length() function) or the keys of maps (to list token names or similar). Related K8s issue to support complex stuff in CRD JSONPath: kubernetes/kubernetes#67268

[aermakov-zalando]

Application is fine, but I disagree with adding errors/problems. We could easily add a status field in credentials-provider to show whether the PCS is healthy or not, but printing raw errors makes the output of zkubectl get pod pretty much unreadable.

[hjacobs]

@aermakov-zalando OK, agreed, will change accordingly and add a new status field.

[aermakov-zalando]

👍

[hjacobs]

👍