We do not need to keep the compiled part in the repo since we are going
to publish to GH Pages but without the results as part of the main branch.

There were duplicates in Diagrams and Images but the ones from Diagrams
were references. The new pipeline expects images in the Images folder though.
Since the files were identical, this commit removes the png files from
the Diagrams folder and makes sure that we are using the ones from Images.

This commit also adds the basic build and setup scripts for the new
workflow.

The goal was to re-publish the original, last published version. For that
I added a fixed date to the meta-data that I took from the last version
I could find.

This commit adds the GH Actions to build a PR as well as the ones to publish.
To keep things consistent, this commit also updates the README to make sure
that links in the README will work again.