feat: add external-dns for managing public DNS records (#288)

cluster/apps/default/echo-server/helm-release.yaml

@@ -30,6 +30,8 @@ spec:
       enabled: true
       annotations:
         cert-manager.io/cluster-issuer: "letsencrypt-production"
+        external-dns.alpha.kubernetes.io/target: "ipv4.${SECRET_DOMAIN}"
+        external-dns/is-public: "true"
         hajimari.io/enable: "true"
         hajimari.io/icon: "video-input-antenna"
         traefik.ingress.kubernetes.io/router.entrypoints: "websecure"