JupyterBook 2 plugin

I created a plugin for h5p for embedding exercises in Jupyter Book 2.  An example can be found here: https://tud-jb-templates.github.io/JB2_plugins/grasple/ at the bottom of the page (note, I created one for grasple as well).

What the plugin does is it creates a styled admonition, embeds an iframe in it, styles the layout using CSS, embeds the title which is specified in the h5p quiz question (so it comes with the metadata provided by H5P), and includes an exercise number in the title. It should be do-able to do even more with the metadata, e.g. make the CSS size (especially height) dependent. 

Any ideas to further develop the plugin are welcome.