Input job settings JSON support

[KevinSayers]

The input parameters must currently be provided in YAML, though CWL supports both YAML and JSON. Implementing a JSON parser should be easier for the parameters file as the number of levels is more limited.

[pditommaso]

Even it should be so difficult, I would give this very low priority. The important thing is being able to have a prototype give the input in YAML. JSON support can be added in a second step.