Notebook rendering: handle metadata.scrolled

Imported from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/20083

What does this MR do?

Handle "scrolled" cell outputs in Jupyter Notebooks (toggled in Jupyter by clicking on Out [XX]).

Are there points in the code the reviewer needs to double check?

This probably need to happen through a CSS class.

Why was this MR needed?

Notebooks can include large outputs that have been folded from Jupyter, but that take a considerate amount of page space when viewed on GitLab.

Screenshots (if relevant)

Before behavior:

After behavior:

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)