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/api-datatypes.go

@@ -36,8 +36,6 @@ type DeletedObject struct {
 	DeleteMarkerMTime DeleteMarkerMTime `xml:"DeleteMarkerMTime,omitempty"`
 	// Status of versioned delete (of object or DeleteMarker)
 	VersionPurgeStatus VersionPurgeStatusType `xml:"VersionPurgeStatus,omitempty"`
-	// PurgeTransitioned is nonempty if object is in transition tier
-	PurgeTransitioned string `xml:"PurgeTransitioned,omitempty"`
 }
 
 // DeleteMarkerMTime is an embedded type containing time.Time for XML marshal
@@ -64,8 +62,6 @@ type ObjectToDelete struct {
 	VersionPurgeStatus VersionPurgeStatusType `xml:"VersionPurgeStatus"`
 	// Version ID of delete marker
 	DeleteMarkerVersionID string `xml:"DeleteMarkerVersionId"`
-	// PurgeTransitioned is nonempty if object is in transition tier
-	PurgeTransitioned string `xml:"PurgeTransitioned"`
 }
 
 // createBucketConfiguration container for bucket configuration request from client.