Add filtering for notification receivers

Set default filtering regexes for email, slack
and pushkin. Set param prometheus_server_alert_label_route
to include all current receivers.

PROD-18981

Change-Id: Ia58914db427bf3249ae12d7bf02f4dd36bb277dc
diff --git a/prometheus/alertmanager/notification/email.yml b/prometheus/alertmanager/notification/email.yml
index 4daec23..fdbc05e 100644
--- a/prometheus/alertmanager/notification/email.yml
+++ b/prometheus/alertmanager/notification/email.yml
@@ -9,7 +9,7 @@
               receiver: SMTP
               match_re:
                 - label: route
-                  value: email
+                  value: '(.*email.*)'
               continue: true
         receiver:
           SMTP: