Create Draft of Structurizr Model + Initial View (Context & Scope)

Description  

Based on the decisions documented in [reference](https://nextcloud.fitko.de/f/2070479), an initial Structurizr model shall be created.  

This includes:  

• modeling the relevant components, interfaces, and structures in the Structurizr model  

• creating an initial view focusing on Context & Scope  

The goal is to establish a foundation for reviewing the most important aspects of the model and views, align them with the requirements, and adjust or refine them as needed.

AC

• A Structurizr model is created and versioned.  
• The model reflects the components and interfaces described in the decision document.  
• An initial Context & Scope view is created.  
• All points from the decision document are either implemented or documented as open issues.  
• Model and view are prepared for a domain/expert review.