Add different background colors to header with commities and section

[dakaza98]

On the old systems, the header with committies and sections have three different themes. Black, white and blue. Those themes should be available on moore. Every site should get to make their own choise on which theme to use

[Maxxen]

I could work on a PR for this.

Also, perhaps this would be best as a new issue, but are there any interest in providing more committee/site/brand specific styling? I think that Balkå has made an excelent use of custom CSS to create a strong identity with primary and accent colors. I think a basic theme'ing could be implemented by just letting each site define a palette of three colors and then allow blocks to opt in to use site style instead of default.

Pimary: overlays, backgrounds
Secondary: buttons, dividers, headings
Accent: buttons, links, icons

Perhaps it could be reduced down to just Primary and Secondary too, I'm not sure there is any committee that uses more than two really, and I don't think site-specific styling should be too strong. Most blocks should have a uniform style across pages. I would be happy if I could just replace some of the blue accents with red ones (links, buttons) on the river rafting site.

[dakaza98]

I would prefer if you don't create a PR for this. We haven't decided on how this should look or where this setting should exist. We also haven't worked out if this is a priority at the moment. This is something we should leave to dkå. Unless you really need this?

Regarding the website specific styling, it will come. This is one of the major tasks that Dkå will work with during the spring. For now I would suggest using html blocks and overriding the css style like balkå did.