Feature Request: Add authorizer kubernetes capabilities

[fabriziosestito]

To be compliant with the ValidatingAdmissionPolicy CEL environment, we need to add the authorizer library.

Acceptance criteria

• it should be possible for the user to create expressions using the authorizer extensions with the same API provided by Kubernetes (see: https://pkg.go.dev/k8s.io/apiserver/pkg/cel/library#Authz)

Solution you'd like

It is not possible to use directly the library from the Kubernetes apiserver, since it uses client-go. We need instead to create a new library with the same interface as the k8s one, that uses kw context-aware/callback capabilities under the hood.