chore: update prose components styling

[Tahul]

Prose components styling isn't following theming as it is using raw CSS values in lots of places.

I think this could be the subject of a refactor, to stick with our theming values and so ensure consistency across design.

I don't see any problem with using @apply for that task.

As an addition, I think we could move those components into a subfolder (atoms/prose ?) and add the prefix via @nuxt/components config.

Ideally, I think this should be a module in itself too, not be bundled with our defaultTheme directly.

Maybe we could think of a way to share these in the long run, allowing features like distributing Prose styling set for your app.