Added a new entry inside the "New" menu for creating a new nim script file (*.nims)
Added support for editing them inside the editor
Change-Id: I09a514fdd4e4a0e9a78bb557db3e8c7e97683b8d
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>