Initial definition of a generic dppp parset step generation

steps/GenericParsetGeneratorStep.cwl

+cwlVersion: 1.1
+class: CommandLineTool
+baseCommand: [python, '-c']
+
+inputs:
+    step_name:
+        type: string
+        doc: "name of the DPPP step"
+
+    step_type:
+        type: string
+        doc: "type of the DPPP step"
+
+    step_arguments:
+        type: array<string>
+        doc: "List of key=value parameters to pass"
+
+outputs:
+    output_file:
+        type: File
+        doc: "Parset output file"