Backport of [NET-4122] Doc guidance for federation with externalServers into release/1.0.x#2604

hc-github-team-consul-core merged 1 commit intorelease/1.0.xhashicorp/consul-k8s:release/1.0.xfrom

backport/zalimeni/net-4122-externalservers-wanfed-k8sauthmethodhost-guidance/definitely-smashing-starlinghashicorp/consul-k8s:backport/zalimeni/net-4122-externalservers-wanfed-k8sauthmethodhost-guidance/definitely-smashing-starlingCopy head branch name to clipboard