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/erasure.go

@@ -79,7 +79,7 @@ func (er erasureObjects) NewNSLock(bucket string, objects ...string) RWLocker {
 // Shutdown function for object storage interface.
 func (er erasureObjects) Shutdown(ctx context.Context) error {
 	// Add any object layer shutdown activities here.
-	closeStorageDisks(er.getDisks())
+	closeStorageDisks(er.getDisks()...)
 	return nil
 }