Use the generated openapi java parts instead of the manually implemented model classes in sechub-systemtest

[winzj]

Situation

Currently we use the manually implemented model classes for example from sechub-commons-model. Step by step we want to use the model classes generated from the openapi.yaml file. If everything was migrated we do not have to maintain both ways in the future.

Wanted

Use some of the generated classes in one gradle submodule.

Important notice

Currently the gradle submodule sechub-openapi-java-client contains all generated classes of the openapi.yaml file.

Solution

• split sechub-openapi-java-client into sechub-openapi-java-client contain the api classes and sechub-openapi-java-model containing the models and helpers if necessary
• use the generated model classes inside sechub-systemtest
• use the generated model classes in additional gradle submodules if it is easy to refactor