Downstream packages to start requiring type-specific attributes

[gracebrownecodes]

As per the discussion in chop-dbhi/data-models-service#20, the "reasonable default" behavior for missing attributes on types is causing problems and, frankly, seems hackish. These files should be the single source of truth and there shouldn't be a default behavior buried in some downstream package that determines field type attributes.

We need to fill in desired lengths, precisions, scales, etc across the repo.