Include "value only" flag for `bake`

[d98762625]

Is your feature request related to a problem? Please describe.
Currently when you POST to /bake it returns a type and a value. If someone wanted to write the converted input to file, they would need to do some post-processing to extract the value from the returned data.

There could be a valuesOnly flag or property that the user could set, and then only the value would be returned.

Describe the solution you'd like
if valuesOnly is truthy
return body only contains dish.value
outputType is still honoured