Add new fields for English translation on articles, events and project articles

[CJGutz]

Is your feature request related to a problem? Please describe.
It should be possible to add translation for different fields in articles, events and project articles. If you find any other places were this is necessary, add there as well. For example should article content and ingress both have the possibility to have English translation. Norwegian should always be the default. There should be an English field in frontend to add this. When looking at the content that can be translated, it should change with the selected locale in the top right.

Follow this documentation for a possible solution to implement this: https://django-modeltranslation.readthedocs.io/en/latest/usage.html

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