widget-factory: Add Keyboard Shortcuts menu item

Closes: GNOME/gtk#916
2 jobs for bye-app-menu-gtk3 in 8 minutes and 9 seconds (queued for 5 minutes and 11 seconds)
Status Job ID Name Coverage
  Build
passed #114401
build

00:08:09

manual #114402
win32 allowed to fail manual
msys2-mingw32