* Removes discovery v1alpha1 API
* Replaces per Endpoint Topology with a read only DeprecatedTopology
in GA API
* Adds per Endpoint Zone field in GA API
- Remove feature gate consideration from EndpointSlice validation
- Deprecate topology field, note that it will be removed in future
release
- Update kube-proxy to check for NodeName if feature gate is enabled
- Add comments indicating the feature gates that can be used to enable
alpha API fields
- Add comments explaining use of deprecated address type in tests
In addition to adding NodeName, this notes that the topology field will
be deprecated soon. It also removes the IP address type that was
deprecated in Kubernetes 1.17 and intended to be removed in 1.20.
This updates EndpointSlice port validation to mirror the validation
already in use for Service and Endpoint ports. This is required to
ensure all valid Service ports can be mapped directly to EndpointSlice
ports.