appFavorites: Automatically update desktop file names in user settings

This adds a table with mappings for GNOME apps that have recently
renamed their desktop files, and uses that to update the desktop names
saved in user settings with the new values.

https://bugzilla.gnome.org/show_bug.cgi?id=729429
popupMenu: Fix PopupImageMenuItem

https://bugzilla.gnome.org/show_bug.cgi?id=733540