Feat/dark theme support

[skjalgepalg]

Add support for a default dark theme in core-docs

• opt-in via configurable options

<script>
  window.coreDocs = {
    theme: { 
      label: 'dark mode', // theme switch label (default: 'dark mode')
      prefers: true // use system settings for light or dark mode (default: true)
    }
  }
</script>

• theme optionally can adhere to user preferences prefers-color-scheme: dark
  • theme can be toggled by used and is saved in current session only
  • user toggled theme has higher presidency then system theme (toggle > prefers-color-scheme: dark)
• possible to override CSS custom properties to control themes
• migrate from deprecated code-prettify to highlight.js
• use accessibility friendly code highlight themes A 11 Y DARK/LIGHT
• toggle custom classes in code examples and demos with conditional classes class="{{ 'light' : 'dark' }}"
• migrate to sass from css
• default options; start core docs without window.coreDocs
• extract styles to separate css file (browser seems to resolve it faster then when injected through js)

[skjalgepalg]

Screenshot of docs-page in default dark theme with visible toggle

[skjalgepalg]

Burde legge inn et notat i docs om at vi har tweaket noen av fargene i a11y-light for å fungere med noe mørkere bakgrunn

[klizter]

Burde legge inn et notat i docs om at vi har tweaket noen av fargene i a11y-light for å fungere med noe mørkere bakgrunn

ordner det 👨‍🔧