Update prometheus to v2.9.2

Drop privileged flag and running node-exporter as root user

Fixes stefanprodan#137

Update prometheus to v2.9.1

Update prometheus to v2.9.0

Update prometheus to v2.9.0

Update pushgateway to v0.8.0

Update grafana to v6.1.3

Update grafana to v6.1.2

Update alertmanager to v0.16.2

Update grafana to v6.1.0