Allow to provision additional Grafana datasources

[Infra-Red]

Opsfile example:

- type: replace
  path: /instance_groups/name=grafana/jobs/name=grafana/properties/grafana/datasources?/delete
  value:
    - name: Cloudwatch
      orgId: 1

- type: replace
  path: /instance_groups/name=grafana/jobs/name=grafana/properties/grafana/datasources?/create
  value:
    - name: Cloudwatch
      type: cloudwatch
      orgId: 1
      jsonData:
        authType: keys
        defaultRegion: eu-central-1
      secureJsonData:
        accessKey: "<my-access-key>"
        secretKey: "<my-secret-key>"

[frodenas]

Thanks @Infra-Red!