agent: Adjust SNAT conditions for direct routing mode
agent: Adjust SNAT conditions for direct routing mode

When not in tunneling mode, be more restrictive when to SNAT.

Ingress:
* Do not SNAT if source is in cluster range

Egress:
* Do not SNAT if destination is in cluster range

If load-balancing occured by kube-proxy, leave it up to kube-proxy

Signed-off-by: Thomas Graf <5f50a84c1fa3bcff146405017f36aec1a10a9e38@cilium.io>

tklauser/cilium,tgraf/cilium,michi-covalent/cilium,eloycoto/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,scanf/cilium,eloycoto/cilium,scanf/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,eloycoto/cilium,eloycoto/cilium,scanf/cilium,eloycoto/cilium,cilium-team/cilium,tklauser/cilium,scanf/cilium,scanf/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,scanf/cilium,cilium/cilium,eloycoto/cilium,tklauser/cilium,tklauser/cilium,cilium-team/cilium,michi-covalent/cilium,scanf/cilium,tklauser/cilium,eloycoto/cilium,michi-covalent/cilium