Overview Dashboard for Grafana

[Sheridan]

As an administrator, I want to see the status of the cluster on a single overview dashboard.

Approximate list:

• Number of nodes, mon, osd, mgr, mds, pg
• Used/free space on OSD
• Used/free space on CephFS
• Cluster health
• Interface traffic
• CPU/memory
• Time synchronization status
• I/O on each OSD