Use Spartan as UI component library

[FelixTJDietrich]

Motivation

We don't want to implement everything ourselves and Spartan/ui is in a relatively good state. Spartan also supports signals and zoneless AFAICS.

Description

• Add all components from Spartan in src/libs/ui
• Replace current components with the ones from Spartan (except for table since our's seems better)
• Minor UI improvements

Screenshots (if applicable)

Checklist

General

• PR title is clear and descriptive
• PR description explains the purpose and changes
• Code follows project coding standards
• Self-review of the code has been done
• Changes have been tested locally
• Screenshots have been attached (if applicable)
• Documentation has been updated (if applicable)

Client (if applicable)

• UI changes look good on all screen sizes and browsers
• No console errors or warnings
• User experience and accessibility have been tested
• Added Storybook stories for new components
• Components follow design system guidelines (if applicable)