Clean up project names in monorepo

[mimarz]

We have landed on using this new naming convention.

# /web
@web/theme  <- apps/theme, but rebuilt using RR7
@web/www <- apps/www
@web/storybook <- apps/storybook 

# /internal
@internal/components <- apps/_components moved and renamed

# /plugins
@plugin/figma <- plugins/figma-plugin, rename folder

# /packages
@digdir/designsystemet
@digdir/designsystemet-css
@digdir/designsystemet-theme
@digdir/designsystemet-react

Suggest doing it step by step. Workflows and relative imports need to be updated.

• PR for just renaming packages
• PR for renaming folders (such as apps). This will have biggest impact so best to save it when not much is being worked on in other branches.

[Barsnes]

This has been started, and we are doing it in smaller steps to not muck up ongoing PRs

[Barsnes]

In https://github.com/digdir/designsystemet/pull/3743#issuecomment-2990158504 we decided to just keep /apps. That means this issue is completed as we have moved the other things in other PRs