Cleanup Nginx proxies for StackLight dashboards

This keeps the backward compatibility for existing deployments
diff --git a/nginx/server/proxy/grafana_web.yml b/nginx/server/proxy/grafana_web.yml
index a1c7c49..66fa46b 100644
--- a/nginx/server/proxy/grafana_web.yml
+++ b/nginx/server/proxy/grafana_web.yml
@@ -1,18 +1,2 @@
-parameters:
-  nginx:
-    server:
-      enabled: true
-      site:
-        nginx_proxy_grafana:
-          enabled: true
-          type: nginx_proxy
-          name: grafana
-          proxy:
-            host: ${_param:stacklight_monitor_address}
-            port: 3000
-            protocol: http
-          host:
-            name: ${_param:cluster_public_host}
-            port: 8084
-            protocol: https
-          ssl: ${_param:nginx_proxy_ssl}
+classes:
+- system.nginx.server.proxy.stacklight.grafana