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>

pkg/iam/policy/admin-action.go

@@ -133,6 +133,13 @@ const (
 	// GetBucketTargetAction - allow getting bucket targets
 	GetBucketTargetAction = "admin:GetBucketTarget"
 
+	// Remote Tier admin Actions
+
+	// SetTierAction - allow adding/editing a remote tier
+	SetTierAction = "admin:SetTier"
+	// ListTierAction - allow listing remote tiers
+	ListTierAction = "admin:ListTier"
+
 	// AllAdminActions - provides all admin permissions
 	AllAdminActions = "admin:*"
 )
@@ -180,6 +187,8 @@ var supportedAdminActions = map[AdminAction]struct{}{
 	GetBucketQuotaAdminAction:       {},
 	SetBucketTargetAction:           {},
 	GetBucketTargetAction:           {},
+	SetTierAction:                   {},
+	ListTierAction:                  {},
 	AllAdminActions:                 {},
 }
 
@@ -232,4 +241,6 @@ var adminActionConditionKeyMap = map[Action]condition.KeySet{
 	GetBucketQuotaAdminAction:   condition.NewKeySet(condition.AllSupportedAdminKeys...),
 	SetBucketTargetAction:       condition.NewKeySet(condition.AllSupportedAdminKeys...),
 	GetBucketTargetAction:       condition.NewKeySet(condition.AllSupportedAdminKeys...),
+	SetTierAction:               condition.NewKeySet(condition.AllSupportedAdminKeys...),
+	ListTierAction:              condition.NewKeySet(condition.AllSupportedAdminKeys...),
 }