Set the "traffic-policy.network.alpha.openshift.io/local-with-fallback"
annotation on LoadBalancer- and NodePort-type services that use the "Local"
external traffic policy.

This commit is related to bug 1960284.

https://bugzilla.redhat.com/show_bug.cgi?id=1960284

* pkg/operator/controller/ingress/load_balancer_service.go
(localWithFallbackAnnotation): New const.  Define the annotation key for
the "local-with-fallback" service annotation.
(desiredLoadBalancerService): Set the "local-with-fallback" annotation when
using the "Local" external traffic policy.
(managedLoadBalancerServiceAnnotations): New variable.  Define the keys for
annotations that the operator manages on LoadBalancer-type services, which
now include the "local-with-fallback" annotation.
(loadBalancerServiceChanged): Fix the update logic to properly handle
annotations with empty values using go-cmp and
managedLoadBalancerServiceAnnotations.
* pkg/operator/controller/ingress/load_balancer_service_test.go
(TestDesiredLoadBalancerService): Verify that the "local-with-fallback"
annotation is set when appropriate.
(TestLoadBalancerServiceChanged): Verify that loadBalancerServiceChanged
properly handles updates to the "local-with-fallback" annotation.
* pkg/operator/controller/ingress/nodeport_service.go
(desiredNodePortService): Set the "local-with-fallback" annotation.
(managedNodePortServiceAnnotations): New variable.  Define the annotation
keys that the operator manages on NodePort-type services.
(nodePortServiceChanged): Check if any of the annotations in
managedNodePortServiceAnnotations have changed.  Update managed annotations
if they have changed.
* pkg/operator/controller/ingress/nodeport_service_test.go
(TestDesiredNodePortService): Verify that the expected annotations are set.
(TestNodePortServiceChanged): Add a test case to verify that
nodePortServiceChanged properly handles updates to the
"local-with-fallback" annotation.