Grafana is a multi-platform open source analytics and interactive visualization web application. It provides charts, graphs, and alerts for the web when connected to supported data sources.
## YunoHost specific features
* installs InfluxDB as time series database
* if the NetData package is installed, configures NetData to feed InfluxDB every minute
* installs Grafana as dashboard server
* creates a Grafana Data Source to fetch data from InfluxDB (and hence NetData!)
* creates a default dashboard to plot some data from NetData (doesn't cover every metric, can be greatly enhanced!)
