Support for remote tier management (#12090)

With this change, MinIO's ILM supports transitioning objects to a remote tier.
This change includes support for Azure Blob Storage, AWS S3 compatible object
storage incl. MinIO and Google Cloud Storage as remote tier storage backends.

Some new additions include:

 - Admin APIs remote tier configuration management

 - Simple journal to track remote objects to be 'collected'
   This is used by object API handlers which 'mutate' object versions by
   overwriting/replacing content (Put/CopyObject) or removing the version
   itself (e.g DeleteObjectVersion).

 - Rework of previous ILM transition to fit the new model
   In the new model, a storage class (a.k.a remote tier) is defined by the
   'remote' object storage type (one of s3, azure, GCS), bucket name and a
   prefix.

* Fixed bugs, review comments, and more unit-tests

- Leverage inline small object feature
- Migrate legacy objects to the latest object format before transitioning
- Fix restore to particular version if specified
- Extend SharedDataDirCount to handle transitioned and restored objects
- Restore-object should accept version-id for version-suspended bucket (#12091)
- Check if remote tier creds have sufficient permissions
- Bonus minor fixes to existing error messages

Co-authored-by: Poorna Krishnamoorthy <poorna@minio.io>
Co-authored-by: Krishna Srinivas <krishna@minio.io>
Signed-off-by: Harshavardhana <harsha@minio.io>

cmd/gateway-unsupported.go

@@ -273,3 +273,13 @@ func (a GatewayUnsupported) Health(_ context.Context, _ HealthOptions) HealthRes
 func (a GatewayUnsupported) ReadHealth(_ context.Context) bool {
 	return true
 }
+
+// TransitionObject - transition object content to target tier.
+func (a GatewayUnsupported) TransitionObject(ctx context.Context, bucket, object string, opts ObjectOptions) error {
+	return NotImplemented{}
+}
+
+// RestoreTransitionedObject - restore transitioned object content locally on this cluster.
+func (a GatewayUnsupported) RestoreTransitionedObject(ctx context.Context, bucket, object string, opts ObjectOptions) error {
+	return NotImplemented{}
+}