Implement OnyxColorSchemeDialog

[larsrickert]

Why?

We want to offer a component where the user can select which appearance he wants to have the application in (light/dark/auto).

Design

Figma

Acceptance criteria

• [x] the design is implemented
• [x] the API integrates nicely with vueuse
• [x] the current docs are updated
• [x] when the dialog opens, the currently selected radio button is focused

Definition of Done

• The following component requirements are implemented:
  • [x] example usage added to apps/alpha-test-app/src/App.vue
• [x] covered by component tests
• [x] screenshot tests are updated
• [x] updated version + documentation is deployed
• [x] Storybook can show the feature
• [x] Set task to In Approval

Approval

• Storybook
• Docs
• [x] approved by designer @jannick-ux
• [x] approved by dev @BoppLi