do not split keywords

[jze]

Currently keywords are split after comma:

https://github.com/ckan/ckanext-dcat/blob/eb1aee013687a40d0366a2fe44546917ee960bfc/ckanext/dcat/profiles.py#L160-L164

In the field of chemistry there are keywords that contains commas. They will be destroyed by this. Therefore, keywords should not be split or at least this behavior should be configurable.

[amercader]

@jze Back in ancient times this was implemented to prevent validation errors: https://github.com/ckan/ckanext-dcat/commit/f90e8ad2ea3b982a4dc1ba700d7438d9f0d13dd3 Perhaps this is no longer needed in modern CKAN versions, or perhaps we still need to escape them somehow. If you could investigate what happens when commas are allowed and/or some workarounds we can definitely implement something to allow it.

[thorge]

In the DCAT specification, keywords are treated as literals, indicating that special characters should be permitted. In our implementation, we have commented out the code responsible for splitting keywords, and it hasn't resulted in any adverse effects. However, other might experience issues with this..