Make use of ListBox sort functions
After crashes when one changed the sort order, it turns out that ALL pages are being deleted and rebuild when one changes the sort order via the menu. (in the crash case it turned out that we even removed the search page, which was still assumed to exist). Rebuilding the Listboxes of all open pages is not a good idea, we should make use of the Listbox sort functions (https://developer.gnome.org/gtk3/stable/GtkListBox.html#GtkListBoxSortFunc) (gtk_list_box_set_sort_func) to just resort the existing list.
Related: https://gitlab.gnome.org/World/PasswordSafe/-/issues/268