Add theme-color <meta> tag and dynamically change the theme-color when
switching into / out of dark mode.
It use the same colours as in the nav-bar component, but I don't think it's possible to access the Windi CSS colour definitions, so I had to hard core the hex values.
The theme-colour <meta> tag needs to be present in the HTML, otherwise `querySelector` returns null.
Rewrite of the UI using Typescript, Vue3, Windicss and Vite. The design should be close to the current one with some changes:
- latest pipeline in a sidebar on the right
- secrets and registry as part of the repo-settings (secrets and registry entries shouldn't be used as much so they can be "hidden" under settings IMO)
- start page shows list of active repositories with button to enable / add new ones (currently you see all repositories and in most cases you only add new repositories once in a while)
