Add translation for norsk bokmål (nb_NO)

First, add translation files and make it show up in Weblate.

Whats wrong with the existing translation files?

https://translate.edugit.org/languages/nb_NO/aleksis/

created merge request !264 (merged) to address this issue

mentioned in merge request !264 (merged)

mentioned in commit 702c6bbc

mentioned in commit 85e2d0e0

closed via merge request !264 (merged)

mentioned in commit 1c73d1ea