ilm: Remove object in HEAD/GET if having an applicable ILM rule (#11296)

Remove an object on the fly if there is a lifecycle rule with delete
expiry action for the corresponding object.

cmd/object-api-datatypes.go

@@ -237,6 +237,11 @@ type ObjectInfo struct {
 	backendType BackendType
 
 	VersionPurgeStatus VersionPurgeStatusType
+
+	// The total count of all versions of this object
+	NumVersions int
+	//  The modtime of the successor object version if any
+	SuccessorModTime time.Time
 }
 
 // MultipartInfo captures metadata information about the uploadId