Improvement: Metamodel corrections

[aschemmel-tech]

Important

Make sure to link this issue with the PR for your improvement.

Metamodel and the related workproducts needs corrections until all warnings disappear to be able to make these "errors" to stop the Doc build.

[aschemmel-tech]

Following problems are still in the metamodel/document generation:

• std_req_iso26262_ still creates warnings as the checks expect an "architecture element" or "feature"
• roles are displayed with "safety" and "security" attributes
• workflows are displayed with "is input to" instead of "has input" or just "input" - likewise for "output"