fix: admin info output and improve overall performance (#10015)

- admin info node offline check is now quicker
- admin info now doesn't duplicate the code
  across doing the same checks for disks
- rely on StorageInfo to return appropriate errors
  instead of calling locally.
- diskID checks now return proper errors when
  disk not found v/s format.json missing.
- add more disk states for more clarity on the
  underlying disk errors.

cmd/storage-rest-client.go

@@ -190,7 +190,13 @@ func (client *storageRESTClient) DiskInfo() (info DiskInfo, err error) {
 	}
 	defer http.DrainBody(respBody)
 	err = gob.NewDecoder(respBody).Decode(&info)
-	return info, err
+	if err != nil {
+		return info, err
+	}
+	if info.Error != "" {
+		return info, toStorageErr(errors.New(info.Error))
+	}
+	return info, nil
 }
 
 // MakeVolBulk - create multiple volumes in a bulk operation.