Height/Width/Duration Validator POC

[digitaldogsbody]

Proof of concept for #144

Still to do, pending discussion in #170:

• Convert to skeleton modifier script instance
• Apply to other places that have H/W/D
  • This could possibly be more efficient by being applied to the Class metaclass that all HWD-havers inherit from.
  • Make use of https://docs.pydantic.dev/usage/validators/#field-checks
  • nb: would have to re-add the if 'height'' in values etc code that was removed, as this would no longer be always True (other Class inheritors do not have those fields
• Regenerate skeleton
• Open tickets for:
  • Updating existing tests
  • Updating existing recipes
  • Updating make_canvas_from_iiif helper