chore: drop dns_zone from site configuration

The only place this was used was for Argo Workflows but we need the Dex
URL and we need the Ingress URL for the service so having this as one
value would have never worked. To actually do this you need to use the
documentation configuration. This leaves dns_zone in place, because
that's still used in the ArgoCD deployment.

Author: cardoe

docs/deploy-guide/extra-sites.md

@@ -27,7 +27,6 @@ place it where we've cloned understack. A complete file would look like:
 # this can remain as the literal value and will ensure it computes the right path
 UC_DEPLOY="$(cd "$(dirname ${BASH_SOURCE[0]})" && git rev-parse --show-toplevel)"
 DEPLOY_NAME="my-site"
-DNS_ZONE=home.lab
 UC_DEPLOY_EMAIL="my@email"
 NO_ARGOCD=yes
 ```
@@ -69,7 +68,6 @@ metadata:
     uc_repo_ref: HEAD
     uc_deploy_git_url: "${UC_DEPLOY_GIT_URL}"
     uc_deploy_ref: HEAD
-    dns_zone: "${DNS_ZONE}"
   labels:
     argocd.argoproj.io/secret-type: cluster
 type: Opaque

go/understackctl/cmd/argocd/templates/argoSecretDeployRepo.tmpl

@@ -16,4 +16,3 @@ metadata:
     uc_repo_ref: "HEAD"
     uc_deploy_git_url: "{{ .UC_DEPLOY_GIT_URL }}"
     uc_deploy_ref: "HEAD"
-    dns_zone: "{{ .DNS_ZONE }}"