EndpointSlice Support

[pgold30]

Description:
EndpointSlice is now enabled by default in Kubernetes and offers some solid performance benefits for clusters with large Endpoint sets. It might be worthwhile to support consuming EndpointSlice, at least as optional.

The lack of EndpointSlices implementation is unfortunately impacting production for us now. Since Kubernetes v1.22, Services that exceed 1000 Pods/network endpoints, Endpoints are now being truncated to a maximum of 1000 items.
Im sure thttps://github.com/kubernetes/ingress-nginx/issues/6017#issuecomment-1170285796 are many other people with the same issue. (same here in Countour)

Outlining the pieces needed to implement this issue @arkodg pointed envoyproxy/gateway#35 (comment)

[Relevant Links:]
projectcontour/contour#2696.
This was shortly discussed envoyproxy/gateway#35 and envoyproxy/gateway#35 (comment)
This was fixed on Feb 15 for nginx-ingress kubernetes/ingress-nginx#8890