Create a reference to a Directory element in another Fragment.
DiskId (DiskIdType) : Sets the default disk identifier for the files contained in this directory. This attribute's value may be overridden by a child Component, Directory, Merge or File element. See the File or Merge elements' DiskId attribute for more information.
FileSource (String) : Used to set the file system source for this DirectoryRef's child elements. For more information, see Specifying source files.
Id (String, required) : The identifier of the Directory element to reference.