generate request/response classes based on DmnDiagramEvaluationModel

[jangalinski]

With the evaluationModel extracted from the diagrams (see #34 ) we know the inputs (name/type) and outputs (name/type) of a diagram evaluation.

Idea: Use this information to generate pojos (data class, ...) that allow type safe request and response of the diagram.

because the dmns are not considered to be present in the project-repository at compile time, we would need to set up a "schema repository" that keep the evaluationModel data at a separate location.
Instead of re-inventing the wheel, we should check if existing code generation/schema registry tools available for java/kotlin/gradle/maven can be used. (avro, json-schema, open-api) ...