Move npm and yarn to new dropdown UI

Context

You use the GitLab Package Registry to publish and share your node packages alongside your source code and pipelines. After a package is published, you can visit the application to view details about hte package and how it was built and you can also find copyable snippets for configuring npm or Yarn and how to install a given package.

That's great, but you probably don't use npm and Yarn. It would be a more efficient use of space to only show you the snippets you need.

Proposal

In !55738 (merged) we introduced a new UI moment to switch among package manager specific installations for Maven and Gradle. We will use the same functionality for npm/Yarn. From a user perspective, GitLab will remember your prior selection and display that in the UI.