Upgrade to Grafana v8.4

{{< docs/shared lookup="upgrade/intro.md" source="grafana" version="<GRAFANA VERSION>" >}}

{{< docs/shared lookup="back-up/back-up-grafana.md" source="grafana" version="<GRAFANA VERSION>" leveloffset="+1" >}}

{{< docs/shared lookup="upgrade/upgrade-common-tasks.md" source="grafana" version="<GRAFANA VERSION>" >}}