feature(themes): introduce dagbladet dark theme

[misund]

This is actually just left-over code that's been lying around on my todo-list for about 8 months. It is not based on any sketches. It is not used anywhere. It is not complete.

Please adjust the settings as much as you'd like, it won't break anything, as nothing is using this theme for anything. This is just meant as a starting point.

The idea is to use all the variables and colors from the dagbladet theme, but then to remap just the skinColors. Didn't work out so well with the Type color, so I had to change it, but most of the palette should be just fine as it is. Fonts and other variables should probably not be affected.

Please tick a box

• feature (A new feature)

If you're adding a feature, is it documented in a storybook story?

• Yes

Are the components you're working on reusable between brands?

• Not working on any components

If you're creating markup, did you add proper semantics?

• Not applicable

(Did you do a CR and see that there is something that we should check for each PR, that are not on the list, please update this document)