Support json path validator argument names

[daikon-cqrs]

Support json path validator argument names

[MrHash]

Thought it was possible to do this easily but first of all the available libs leave a lot to be desired.

Secondly, using flow/jsonpath generally always outputs an array, and it looks impossible to differentiated between a scalar value and a single result in a query. Probably a better approach would be to allow validators to iterate a result set and merge outputs so a single validator can be run iteratively on a path, with results recombined into the response payload. Still need to be able to pass a complete array input into a validator as well.