Recommended way to connect dashboard to multiple lightning nodes?

[bucko13]

Not sure if this even possible with current configuration (although I did see a Draft PR #42 that makes me think it's not yet), but having this capability and having it documented would be very helpful, especially since conceivably lndmon's target audience is more for power uses who are more likely than normal users to have multiple nodes they'd like to manage/monitor.

[Roasbeef]

Atm it only works for a single lnd node. To support multiple nodes, we'll need to add a new label for a node ID, and that's about it.

This attribute should be chained to a map similar to map[string]*lndConfig. From there, multiple instances of the PrometheusExporter should be created for each entry in the map. The label (that string) value, should then be passed in to the exporter as a new param. Finally, all metrics should now include a node ID value.