WorkflowStep Input and Output specifications extra type information

[mr-c]

if valueFrom is used in WorkflowStepInput then the type is not knowable in static analysis.

1. cwltool and others should throw a warning for cwlVersion: 1.3 and newer documents
2. to silence this warning we add a type field to WorkflowStepInput that is highly recommended for valueFrom users. At runtime, if the valueFrom result isn't a match for the type field then this is a permanentFailure.