Add ability to render html of a Juptyer notebook

[firasm]

Instructors often request students to submit jupyter notebooks into PrairieLearn for manual grading.

This feature request would add the ability to render the html from an ipynb in-browser for easier manual grading.

[moveisi]

That would be a fantastic add-on. Right now, our TAs need to download ipynb files first and load it somewhere else to view them for marking.

There are some other files types that would be great to be able to view directly on PL as well, such as PDF and HTML.

[jonatanschroeder]

HTML can be rendered already, check the pl-xss-safe element.