GUI updates, collected.

- Validate against list of valid values, or offer list of suggested values, for `keywords`, `formats`, `type` (more specific discussion required)

- when specifying taxonomic data in the interface, to be stored in the `isAbout` fields, a dummy option should be offered in cases where a species identifier does not apply (e.g. phantoms or other imaging calibration data, _in vitro_ gene expression)

- validate subfields of `extraProperties->origin` according to the logic specified in https://github.com/CONP-PCNO/conp-documentation/blob/master/CONP_DATS_fields.md (in summary, `extraProperties->origin` must contain a value for at least one of the `institution` or `consortium` subfields)

- validate format of `identifier` as a DOI (or an ARK when that is implemented).