Support and export default values on the CWL side

See https://github.com/OpenMS/OpenMS/issues/7720

Improvement of schema code generator: https://github.com/common-workflow-language/schema_salad/pull/893
Updated generated code: https://github.com/common-workflow-lab/cwl-cpp-auto/pull/11
Improved TDL: https://github.com/deNBI-cibi/tool_description_lib/pull/60