Draft: Pipeline for documentation

Address Issue #72.

We use the Forge docker registry. We need to have the Dockerfile of the runner (which is needed to initialize the runner with python and all the dependencies).

The docker image is hosted in the Forge Registry, and it is built only when a change is applied to the Dockerfile or the requirements.txt file.

I also added the CI/CD yaml file which calls the command for testing the documentation. If it does not fail, the pipeline proceed with an OK.