Fix: categories need a clean / validation step

[lwasser]

We need a validator to clean up the categories attr in the pydantic model

Current lists look like this: we want dashes between each word for easier parsing

    - data-retrieval
    - data-extraction
    - data-processing/munging
    - data-deposition
    - data-validation and-testing
    - workflow-automation
    - database-interoperability

will revisit that piece and potential pydantic validators to cleanup.

Originally posted by @lwasser in #93 (comment)