Infer Value Range from the Levels information

[JessyD]

Some questionnaires (like Diagnosis_KSADS from the HBN dataset) do not have Value Range column but this information could be inferred using the levels, which are provided.

[ericearl]

I like this idea, but the more I'm thinking about it the more I feel like we should exclude non-BIDS-valid fields in the data dictionary JSONs... I think they should be added to the end of the Description of any field. What do you think? This thought is based on https://bids-specification.readthedocs.io/en/stable/02-common-principles.html#tabular-files.