Add telegraf ping plugin

Add template for telegraf ping plugin
Add meta for ping confguration
Add NodeDown alert

Change-Id: I8ed64eca9eaeca45e4526528e9bcab795131d914
PROD-related: PROD-27580 (PROD:27580)
diff --git a/metadata/service/support.yml b/metadata/service/support.yml
index efd57d9..934abf7 100644
--- a/metadata/service/support.yml
+++ b/metadata/service/support.yml
@@ -5,3 +5,5 @@
         enabled: true
       prometheus:
         enabled: true
+      telegraf:
+        enabled: true