add external peer configuration to cilum + kube-router docs
add external peer configuration to cilum + kube-router docs

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