Improve local dev override docs and add read-only example

examples/read_only/outputs.tf

@@ -0,0 +1,24 @@
+output "domains" {
+  description = "All visible Dynu domains."
+  value       = data.dynu_domains.all.domains
+}
+
+output "resolved_domain" {
+  description = "Resolved Dynu root domain details for var.hostname."
+  value       = data.dynu_domain.selected.domain
+}
+
+output "resolved_dns_records" {
+  description = "DNS records for the resolved root domain."
+  value       = data.dynu_dns_records.selected.records
+}
+
+output "resolved_domain_id" {
+  description = "Domain ID returned by dynu_dns_records."
+  value       = data.dynu_dns_records.selected.domain_id
+}
+
+output "resolved_domain_name" {
+  description = "Root domain name returned by dynu_dns_records."
+  value       = data.dynu_dns_records.selected.domain_name
+}