Feature Request - Reuse init command for multiple charts

The example configuration suggests using an `init` command for things that require some initial setup, such as getting performance metrics from a database server. In some cases, multiple charts may be fetching data from the same source, so it would be convenient if the sample instance of an `init` command could be reused somehow. This would be useful for e.g. setting up charts for multiple production servers, separately showing CPU load and RAM usage, where both data sets are coming from the same data source.