replace mousepad editor with something else that has spellchecking and better usability

[Patrick]

use sudoedit in Whonix documentation and Whonix software

The wiki tells users to edit files as root using mousepad or kwrite. These are both GUI programs which should not be run as root. GUI applications often contain many security holes and running something like that as root is something you don’t want to do. Running any editor as root is also insecure. I recommend to change it to tell users to use sudoedit which copies the file to a temporary location, edits it as a normal user and then overwrites the original using sudo. This way is much more s…