Sync config v14.2.0 : gitlab: Add commented-out config cdn_host

See upstream Merge request:
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/67710

Author: kkimurak

assets/runtime/config/gitlabhq/gitlab.yml

@@ -35,6 +35,10 @@ production: &base
     host: {{GITLAB_HOST}}
     port: {{GITLAB_PORT}} # Set to 443 if using HTTPS, see installation.md#using-https for additional HTTPS configuration details
     https: {{GITLAB_HTTPS}} # Set to true if using HTTPS, see installation.md#using-https for additional HTTPS configuration details
+
+    # Uncomment this line if you want to configure the Rails asset host for a CDN.
+    # cdn_host: localhost
+
     # The maximum time Puma can spend on the request. This needs to be smaller than the worker timeout.
     # Default is 95% of the worker timeout
     max_request_duration_seconds: 57