feat(grafana): 🎨 Add root_url configuration for server

Adds a root_url configuration for the Grafana server to ensure proper access through the specified URL.

This change enhances the setup by defining the server's root URL, improving accessibility and usability for users.

otc/observability.t09.de/stacks/observability/grafana-operator/manifests/grafana.yaml

@@ -40,6 +40,8 @@ spec:
         - grafana.observability.t09.de
         secretName: grafana-net-tls
   config:
+    server:
+      root_url: "https://grafana.observability.t09.de"
     auth:
       disable_login: "true"
       disable_login_form: "true"