The properties OrderBy and OrderByOn have been added to the Form and SubForm objects.
The ordering sequence defined by OrderBy is effectively applied when OrderByOn is set to True.

Change-Id: I7780e4761f3825f1c678d6ffb38149c5973146e7
Reviewed-on: https://gerrit.libreoffice.org/10697Reviewed-by: Lionel Elie Mamane <lionel@mamane.lu>
Tested-by: Lionel Elie Mamane <lionel@mamane.lu>