Add support for Kubernetes-specific string formats added in Kubernetes Declarative Validation tags (+k8s:format=*)

[aaron-prindle]

The Kubernetes Declarative Validation feature uses several custom string formats for validation in native types. This issue tracks making these formats available for CustomResourceDefinitions (CRDs).

Currently, kube-openapi supports k8s-short-name and k8s-long-name in kubernetes-extensions.go.

We want to also add support for the following additional formats defined in k/k format.go:

• k8s-extended-resource-name
• k8s-label-key
• k8s-label-value
• k8s-long-name-caseless
• k8s-path-segment-name
• k8s-resource-fully-qualified-name
• k8s-resource-pool-name
• k8s-uuid

Likely Implementation Steps (based on existing formats):

1. In kubernetes-extensions.go, follow the pattern used for ShortName and LongName.
2. Define a new type for each format, e.g.:

   // swagger:strfmt k8s-label-key
   type LabelKey string

3. Implement required methods for the type (MarshalText, UnmarshalText, MarshalJSON, UnmarshalJSON, DeepCopyInto, DeepCopy, String).
4. Define a regular expression and max length for validation.
5. Register the format in the init() function:

   func init() {
       // ...
       labelKey := LabelKey("")
       Default.Add(k8sPrefix+"label-key", &labelKey, IsLabelKey)
   }