Add Norwegian language

Problem/Motivation

Most-commonly used language code for Norwegean is NO.
Drupal at the moment does not support this language (code) and it can not be selected from the UI.
There are NN and NB, but they are not the general official language.

Taken from https://www.w3schools.com/tags/ref_language_codes.asp

Norwegian	no
Norwegian bokmål	nb
Norwegian nynorsk	nn

Maybe we need to cross-check all that Drupal provides to all that the browsers support as language codes.

Proposed resolution

Add the missing languages that are generally supported in browsers.

Remaining tasks

Discussion, patch, plan.

User interface changes

New language options in the translation interface.

API changes

None expected.

Data model changes

None expected.

Release notes snippet

New languages added.