Simplify config backup of softwares parameters

To configure the backup of softwares settings and data, Gnome settings and system setings: make an user interface listing settings that can be saved (Ex: Evolution settings and/or mails, printers, look of gnome, firewaal settings, etc...) with checkbutton for all possibilites. For add compatibility with a saftware to Déjà Dup, use a plugin contains the location of file to save and, if necessary, command line to execute in pre/post backup and pre/post restoration (Ex: for Grub settings, Plymouth settings, etc...).