multus: fail if given pod UID does not match Kube API pod UID

If the runtime passes a pod UID via K8S_POD_UID (which both CRIO and
containerd do as of mid-2021) then fail if the pod we get from the
Kube API has a different UID. This would indicate that the pod was
deleted and recreated while Multus was attempting to set up
networking for the old pod instance's sandbox, and it's pointless
to continue setting up a sandbox for a dead pod instance.

Also pass the pod UID through to plugins so they can perform
additional checking and validation on the pods they get from the
Kube API.

Signed-off-by: Dan Williams <dcbw@redhat.com>

pkg/types/types.go

@@ -157,6 +157,7 @@ type K8sArgs struct {
 	K8S_POD_NAME               types.UnmarshallableString //revive:disable-line
 	K8S_POD_NAMESPACE          types.UnmarshallableString //revive:disable-line
 	K8S_POD_INFRA_CONTAINER_ID types.UnmarshallableString //revive:disable-line
+	K8S_POD_UID                types.UnmarshallableString //revive:disable-line
 }
 
 // ResourceInfo is struct to hold Pod device allocation information