illuminatio should also test endpoints

[johscheuer]

In the current implementation illuminatio "only" tests the service ip we should also execute tests that check if the endpoints are directly reachable (no communication over kube-proxy or what ever load balances the service IPs).

This could be helpful to see if both cases are supported/implemented, e.g. I think of some strange behaviour where service IPs are blocked but the direct endpoint call is not blocked or vice versa.