convert output to yaml

[mpadge]

Parallel to #10, also implement ability to convert output to an analogous yaml structure in which users can enter response data for each point, with these responses in this yaml able to be used as input to subsequent calls, to enable both customisation of which tests are run, and ultimately ready report generation which incorporates users' written responses.

[mpadge]

This will no longer be needed, once output format has been properly specified via #19, #20 so it can also be used to pass back as input object.