* AuthN: Add NamespaceID struct. We should replace the usage of encoded namespaceID with this one
* AuthN: Add optional interface that clients can implement to be able to resolve identity for a namespace
* Authn: Implement IdentityResolverClient for api keys
* AuthN: use idenity resolvers
Co-authored-by: Misi <mgyongyosi@users.noreply.github.com>