GtkFileChooser/GtkRecentManager follows https://www.freedesktop.org/wiki/Specifications/desktop-bookmark-spec/ specification to store its recently accessed files.
The history is stored in $HOME/.local/share/recently-used.xbel
Adds an event spy for the xml file used by gtk following the example of the KRecentDocument EventSpy.
It allows to populate recently accessed files from apps using Gtk, including inkscape, gimp...
BUG: 311218