Value depends on type and describes the playlist item.
dashboard_by_id: The value is an internal numerical identifier set by Grafana. This
is not portable as the numerical identifier is non-deterministic between different instances.
Will be replaced by dashboard_by_uid in the future. (deprecated)
dashboard_by_tag: The value is a tag which is set on any number of dashboards. All
dashboards behind the tag will be added to the playlist.
dashboard_by_uid: The value is the dashboard UID