I18n: Update translation ast (95%).

64 translated messages, 3 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nb (74%).

50 translated messages, 17 untranslated messages.

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