chore: drop container labels from cadvisor, require webtop CUSTOM_USER, trim env template comments

alloy/compose.yml

@@ -210,8 +210,9 @@ configs:
       }
 
       prometheus.exporter.cadvisor "integrations_cadvisor" {
-          docker_only = true
-          docker_host = "tcp://127.0.0.1:2375"
+          docker_only            = true
+          store_container_labels = false
+          docker_host            = "tcp://127.0.0.1:2375"
       }
       discovery.relabel "integrations_cadvisor" {
           targets = prometheus.exporter.cadvisor.integrations_cadvisor.targets