docs: Add documentation for the Grafana demo dashboard

Author: ewoud ketele

dashboards/GrafanaDemo/README.md

@@ -0,0 +1,27 @@
+# Grafana Demo
+
+## Data sources used
+- MySQL Accounting database for DIRAC certification
+- ElasticSearch cluster for DIRAC certification
+
+## What plots does the dashboard contain?
+- Production Jobs By Final Minor Status
+- User Jobs By Final Minor Status
+- Job CPU Efficiency By Job Type
+- User Jobs By Job Type
+- User Jobs By Final Minor Stattus
+- Pilots By Status
+
+## How to import this dashboard into another Grafana installation?
+- Create Grafana data sources for the MySQL database and ElasticSearch cluster (both the DIRAC certification versions).
+- Create a new dashboard and in 'Dashboard settings' under 'JSON model' replace the JSON representation of the dashboard with this one.
+- In the JSON file, replace the datasource uid's with the ones for the data sources in your grafana installation. You can find the UID of a data source:
+    - with the [API](https://grafana.com/docs/grafana/latest/developers/http_api/data_source/)
+    - by creating a new visualisation using this data source and looking into the JSON model of the visualisation (right click the title > Inspect > Panel JSON)
+
+```
+"datasource": {
+        "type": "mysql",
+        "uid": "R3A-SHw7z" <- CHANGE THIS VALUE TO THE ONE FOR YOUR INSTALLATION
+      },
+```