Add speedtest cli to Telegraf config

- Install speedtest CLI on cluster leader
- Install speedtest telegraf config on leader
- cleanup hosts in ping list
- Add custom shell script on leader to output speedtest data to influxdb
- improve version checking of Telegraf binary
- bump telegraf version
- allow ' package-latest' to pass ansible-lint

templates/telegraf/speedtest.conf.j2

@@ -0,0 +1,6 @@
+[[inputs.exec]]
+  commands = ["/usr/local/bin/telegraf_speedtest.sh"]
+  interval = "10m"
+  timeout = "1m"
+  name_suffix = "_speedtest"
+  data_format = "influx"