Replace gparted with gnome-disk-utility
Originally created by Tails on #5312 (Redmine)
Gnome Disk Utility gives the opportunity to set up an encrypted partition easily, with a couple of clicks, whereas with GParted you need to use the cryptsetup command line tool. This would be useful for instance for Windows users, who have installed Tails with UNetbootin on an USB pendrive and could then easily encrypt the remaining space of the pendrive after booting Tails.
Cryptsetup is admittedly an easy tool, but since there already is a GUI for doing that, why not implement it?
GNOME disk utility is already installed in Tails 0.7 => done. GParted is also installed as it has a few features g-d-u has not, such as partition and filesystems resizing.