I18n: Update translation ast (81%).

141 translated messages, 31 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nb (91%).

158 translated messages, 14 untranslated messages.

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