Custom HTML5 applet in a (h5p)-box

Hi, 

I have created some simple little apps (e.g. a binary number to decimal converter) that have one html, one css and one js file.

I thought it would be easy to wrap them in a custom h5p content type. I have tried building a minimal h5p content type using the greeting card example as a blueprint. I attached the contents of the html file to the container in the main js file. My custom css and js is in extra files and loaded by the html file. 

so the directory structure is

myapp/
myapp/h5p.json
myapp/content/    (empty directory)
myapp/H5P.minimal 
myapp/H5P.minimal/library.json
myapp/H5P.minimal/minimal.js
myapp/H5P.minimal/index.html
myapp/H5P.minimal/script.js
myapp/H5P.minimal/style.css

If I load this with Lumi it gives an error. Uploading to Moodle gives an error as well.

I then tried to use the iframe-embedder content type to achieve the same goal, but everything I create with it gives an error as well.
I read somewhere that html is not whitelisted... does this mean the h5p file is invalid if it contains a html file?

I feel like the docs I read are not completely up to date. What am I missing?