Add option to display the title of the specified sheet on the cover page of exported Office documents

At the moment, when exporting a wiki page as ODT/RTF with a sheet specified in the URL query string, (e.g. using http://localhost:8080/xwiki/bin/view/Sandbox/?sheet=Sandbox.TestPage1), on the cover page is displayed the title of the respective page (e.g. Sandbox), not the title of the specified sheet (e.g. Sandbox.TestPage1).

It would be nice to have the option to display the title of the specified sheet also on the exported document's cover page, which can be useful in some use-cases.