ReferenceGrant from Route to BackendObjectReference

[mpstefan]

As a user of NKG
I want to allow my Route object to reference services in another namespace via a ReferenceGrant
So that I can utilize services in other namespaces for my application's route.

Acceptance

• When a service is referenced in a Route that does not have a corresponding ReferenceGrant, the status of that Route is set to ResolvedRefs/False/RefNotPermitted
• When a valid ReferenceGrant is created or updated within a namespace that the NKG control plane watches, the Route specified is able to reference services in other namespaces NKG is present.
• No services in other namespaces can be referenced by any Route that does not have a corresponding ReferenceGrant.
• No information is ever exposed about resources in another namespace that do not have a valid ReferenceGrant.
• Update the documentation
  • Update the compatibility doc
  • Add an example for how to reference a service from another namespace in your Route config.