feat(artifact): add OCI references support (#936)

Thanks @jdolitsky et al for kicking off these changes at:
https://github.com/oci-playground/zot/commits/main

Thanks @sudo-bmitch for reviewing the patch

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>

pkg/storage/constants/constants.go

@@ -6,16 +6,18 @@ import (
 
 const (
 	// BlobUploadDir defines the upload directory for blob uploads.
-	BlobUploadDir           = ".uploads"
-	SchemaVersion           = 2
-	DefaultFilePerms        = 0o600
-	DefaultDirPerms         = 0o700
-	RLOCK                   = "RLock"
-	RWLOCK                  = "RWLock"
-	BlobsCache              = "blobs"
-	DuplicatesBucket        = "duplicates"
-	OriginalBucket          = "original"
-	DBExtensionName         = ".db"
-	DBCacheLockCheckTimeout = 10 * time.Second
-	BoltdbName              = "cache"
+	BlobUploadDir            = ".uploads"
+	SchemaVersion            = 2
+	DefaultFilePerms         = 0o600
+	DefaultDirPerms          = 0o700
+	RLOCK                    = "RLock"
+	RWLOCK                   = "RWLock"
+	BlobsCache               = "blobs"
+	DuplicatesBucket         = "duplicates"
+	OriginalBucket           = "original"
+	DBExtensionName          = ".db"
+	DBCacheLockCheckTimeout  = 10 * time.Second
+	BoltdbName               = "cache"
+	ReferrerFilterAnnotation = "org.opencontainers.references.filtersApplied"
+	//
 )