Update master branch (documentation and master branch are out of sync)

[mariofrei]

The video from Federico showing how to make a new question flow does not apply to the master branch. It works for the branch 'onith-covid'. However, in that branch, a test API is used to write data to the database without an API key.

[mariofrei]

While working on getting the master branch in sync with the documentation, we should probably also transfer the wiki to the website in order avoid having two different sources of documentation that are out of sync.