Refactor cert-manager and ExternalDNS configurations

- Updated the namespace for the internal wildcard certificate from 'internal' to 'cert-manager'.
- Adjusted the DNS zone selectors in Let's Encrypt configurations to use CLOUDFLARE_DOMAIN consistently.
- Changed the namespace for the wildcard certificate from 'default' to 'cert-manager'.
- Modified ExternalDNS configuration to use OWNER_ID instead of CLUSTER_ID for TXT owner ID.
- Cleaned up setup-cert-manager.sh by removing unnecessary internal namespace creation and secret duplication.
- Updated certificate wait commands to reflect the new namespace structure.
- Simplified the copying of certificates to the example-admin namespace.
- Removed test service deployment from setup-externaldns.sh for a cleaner setup process.

infrastructure_setup/cert-manager/letsencrypt-prod-dns01.yaml

@@ -19,7 +19,7 @@ spec:
             key: api-token
       selector:
         dnsZones:
-        - "${CLOUDFLARE_DOMAIN}" # This will cover all subdomains
+        - "${CLOUDFLARE_DOMAIN}"
     # Keep the HTTP-01 solver for non-wildcard certificates
     - http01:
         ingress: