[Enhancement] consistent dates in DataCite and SchemaOrg properties

[sneumann]

Hi,
this is a non-urgent change for the SchemaOrg metadata output. Please only fix once a significant number of changes have accumulated in this corner of the repo code.

In https://www.chemotion-repository.net/api/v1/public/metadata/download_json?type=sample&id=108946
I find: "dateCreated": "2024-02-10", "datePublished": "2024-02-10" which are the same date.

Things should be consistent with the DataCite metadata, e.g.
https://www.chemotion-repository.net/api/v1/public/metadata/download?type=sample&id=108946
which has

  <dates>
    <date dateType="Submitted">2024-01-10 08:57:59 UTC</date>
    <date dateType="Accepted">2024-02-10 12:14:27 UTC</date>
  </dates>

So maybe dateCreated should map to Submitted ?

Yours,
Steffen