Add selectable fields support

[pmalek]

Problem statement

Kubernetes 1.31 has promoted CRD selectable field to beta and enabled it by default. 1.32 has promoted it to GA.

• Official docs: https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/#custom-resource-field-selectors
• KEP KEP: Custom Resource Field Selectors kubernetes/enhancements#4359

This proposal is about adding a selectable fields to CRDs in this repository

This could be beneficial in several scenarios, in projects that use these CRDS (KIC & KGO) and on the command line using kubectl.

Caveat

Introduction of this field to our CRDs would immediately bump the minimum supported k8s version to 1.31 so a decision on the timing for this feature would need to be made.

Acceptance criteria

• A decision is made about the timing of adding this feature.
• Fields for CRDs in this repo are reviewed and a list of those that would be good candidates for selectable fields is prepared
• CRDs in this repo have selectable fields added as per the list mentioned above.