Enable "environment" label for every metric by default

Change-Id: I207ba785c82e072e39f3c7d4cb5f17a904dd9b7d
Related-PROD: PROD-22051
diff --git a/prometheus/server/container.yml b/prometheus/server/container.yml
index 99873ad..8bda131 100644
--- a/prometheus/server/container.yml
+++ b/prometheus/server/container.yml
@@ -1,3 +1,10 @@
 classes:
 - service.prometheus.server.container
 - system.prometheus.server
+parameters:
+  _param:
+    prometheus_environment_label: ${_param:cluster_domain}
+  prometheus:
+    server:
+      config:
+        environment_label: ${_param:prometheus_environment_label}