x11/xdg-user-dirs-gtk: new port
xdg-user-dirs-gtk is a companion to xdg-user-dirs that integrates
it into the GNOME desktop and Gtk applications.
It gets run during login and does two things:
- Tracks changes of locale and prompts the user so the directories
can be changed.
- Creates a default gtk bookmarks file if there is none, based
on a set of xdg user dirs.
PR: 286697