The prometheus metrics refractoring (#8003)

The measures are consolidated to the following metrics

- `disk_storage_used` : Disk space used by the disk.
- `disk_storage_available`: Available disk space left on the disk.
- `disk_storage_total`: Total disk space on the disk.
- `disks_offline`: Total number of offline disks in current MinIO instance.
- `disks_total`: Total number of disks in current MinIO instance.
- `s3_requests_total`: Total number of s3 requests in current MinIO instance.
- `s3_errors_total`: Total number of errors in s3 requests in current MinIO instance.
- `s3_requests_current`: Total number of active s3 requests in current MinIO instance.
- `internode_rx_bytes_total`: Total number of internode bytes received by current MinIO server instance.
- `internode_tx_bytes_total`: Total number of bytes sent to the other nodes by current MinIO server instance.
- `s3_rx_bytes_total`: Total number of s3 bytes received by current MinIO server instance.
- `s3_tx_bytes_total`: Total number of s3 bytes sent by current MinIO server instance.
- `minio_version_info`: Current MinIO version with commit-id.
- `s3_ttfb_seconds_bucket`: Histogram that holds the latency information of the requests.

And this PR also modifies the current StorageInfo queries

- Decouples StorageInfo from ServerInfo .
- StorageInfo is enhanced to give endpoint information.

NOTE: ADMIN API VERSION IS BUMPED UP IN THIS PR

Fixes #7873

pkg/madmin/service-commands.go

@@ -53,7 +53,7 @@ func (adm *AdminClient) serviceCallAction(action ServiceAction) error {
 
 	// Request API to Restart server
 	resp, err := adm.executeMethod("POST", requestData{
-		relPath:     "/v1/service",
+		relPath:     adminAPIPrefix + "/service",
 		queryValues: queryValues,
 	})
 	defer closeResponse(resp)
@@ -85,7 +85,7 @@ func (adm AdminClient) ServiceTrace(allTrace, errTrace bool, doneCh <-chan struc
 			urlValues.Set("all", strconv.FormatBool(allTrace))
 			urlValues.Set("err", strconv.FormatBool(errTrace))
 			reqData := requestData{
-				relPath:     "/v1/trace",
+				relPath:     adminAPIPrefix + "/trace",
 				queryValues: urlValues,
 			}
 			// Execute GET to call trace handler