feat: Single drive XL implementation (#14970)

Main motivation is move towards a common backend format
for all different types of modes in MinIO, allowing for
a simpler code and predictable behavior across all features.

This PR also brings features such as versioning, replication,
transitioning to single drive setups.

cmd/utils.go

@@ -906,6 +906,8 @@ func getMinioMode() string {
 		mode = globalMinioModeErasure
 	} else if globalIsGateway {
 		mode = globalMinioModeGatewayPrefix + globalGatewayName
+	} else if globalIsErasureSD {
+		mode = globalMinioModeErasureSD
 	}
 	return mode
 }