Set up alerting (in Grafana?)

[scy]

We need to have alerts for certain important things:

• system load too high
• RAM running low
• disk running low
• 46elks balance running out (Monitor 46elks balance #210)

@dpolakovics, I’d like to do this in cooperation with you, since you certainly already have some kind of alerting in place for the epicenter.works infrastructure.