fix: add missing minio_s3_requests_total (#15070)

PR #15052 caused a regression, add the missing metrics back.

Bonus:

- internode information should be only for distributed setups 
- update the dashboard to include 4xx and 5xx error panels.

cmd/generic-handlers.go

@@ -282,7 +282,9 @@ func setHTTPStatsHandler(h http.Handler) http.Handler {
 		r.Body = meteredRequest
 		h.ServeHTTP(meteredResponse, r)
 
-		if strings.HasPrefix(r.URL.Path, minioReservedBucketPath) {
+		if strings.HasPrefix(r.URL.Path, storageRESTPrefix) ||
+			strings.HasPrefix(r.URL.Path, peerRESTPrefix) ||
+			strings.HasPrefix(r.URL.Path, lockRESTPrefix) {
 			globalConnStats.incInputBytes(meteredRequest.BytesRead())
 			globalConnStats.incOutputBytes(meteredResponse.BytesWritten())
 		} else {