Split evince-previewer into its own package
    
    evince-previewer is used by the GTK printing dialog to preview
    documents before printing. When Evince is distributed as a Flatpak
    (for example in Silverblue), GTK can't find the previewer at
    %{_bindir}/evince-previewer
    
    See https://github.com/fedora-silverblue/issue-tracker/issues/122