I18n: Update translation nb (87%).

182 translated messages, 26 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation vi (73%).

153 translated messages, 55 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nb (100%).

208 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).