Update links in documentation

What does this MR do and why?

Chore: update links to git repository and tutorial on website.

Please look at the link in README rule 153: http://www.jeuring.net/. I am not sure if this link should be updated, but I think it is fine.

MR acceptance checklist

• The code in the merge request completes all the elements in the ticket it is linked to.
• The code is sufficiently tested, use HPC as described in the DEVELOPER.md to check this.
• All tests pass.
• There are no new HLint warnings.
• The code adheres to the style guide and is properly formatted.
• The code structure makes sense and can not be easily improved.
• No unused/commented out code and no TODO comments.

Closes V25B-751