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)
(cherry picked from commit 754ebbfbea65329012c1c8bc05772ad22985c59c)
4 files changed