Offer to translate all .desktop files in Rosetta
.desktop file translations are one of the most visible items on the desktop. Rosetta should provide a special edit mode which groups all .desktop file translations together.
The POT files contain the source of a string, so Rosetta already has all the required information. So this is only a UI issue, we do not need to change infrastructure for that.
* Blueprints in grey have been implemented.