Advanced Scrum use cases tutorial

What does this MR do and why?

• The introductory Scrum tutorial !134551 (merged) was too long.
• This MR splits the advanced use cases into a separate tutorial.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

There are no changes to the application. This is a documentation-only change.

How to set up and validate locally

Visit the docs site locally and go to /ee/tutorials/, then select the Scrum tutorial.