Create monitoring-mixin

[thedodd]

• Create monitoring-mixin for Grafana dash, Alerts, &c
  • Operator basics.
  • Stream basics.
  • Add metric to Stream for last compacted offset.
  • Stream subscription templates with alerting for blocked sub (no registered consumers for a particular group).
  • Pipeline templates with alerting for blocked pipelines (no registered consumers for a particular stage).
  • All items should have Grafana alerting included.
• Add docs to chart and guide on how to integrate the monitoring mixins into user's systems:
  • https://monitoring.mixins.dev/#how-to-use-mixins
  • https://github.com/grafana/helm-charts/tree/main/charts/grafana#sidecar-for-dashboards
• Add docs to guide on monitoring, all of the prom metrics exposed &c.
• Create PR to mixin repo to have this code added as. Moved to Add Hadron monitoring mixin to official mixin repo #119