Add PROMETHEUS_ALERT_RESEND_DELAY in Prometheus Docker config

+ increase default sf-notifier workers to 8

Change-Id: I156659e27cda4970fe49312b5778b08a21ea1981
Related-bug: PROD-35421
diff --git a/docker/swarm/stack/monitoring/sf_notifier.yml b/docker/swarm/stack/monitoring/sf_notifier.yml
index ff32a0b..e2e5435 100644
--- a/docker/swarm/stack/monitoring/sf_notifier.yml
+++ b/docker/swarm/stack/monitoring/sf_notifier.yml
@@ -2,7 +2,7 @@
 - system.prometheus.sf_notifier.container
 parameters:
   _param:
-    sf_notifier_workers: 4
+    sf_notifier_workers: 8
     sf_notifier_buffer_size: 32768
     sf_notifier_alert_id_hash_func: sha256
   docker: