What kind of changes does this PR include?

• Fixes or refactors
• A new challenge
• Additional documentation
• Something else

To Do

• Embed the secret variable in https://github.com/OWASP/wrongsecrets/blob/master/.github/scripts/docker-create.sh and make sure it lands in a file in the docker container
• create a challenge that reads the secret from that file and teaches why this is a bad idea (See contributing.md)

Relations

Closes #812

Checklist:

• All the contributions made are solely the work of me and my co-authors
• I tested the changes in this PR (if applicable)
• I added unit tests to ensure my change works (when change in Java or on front-end code)
• I added UI tests to ensure my UI changes work (when change in the overall UI, not needed if just adding a challenge)
• The PR passes pre-commit hooks and automated tests