Check compatibility with Triply dataset descriptions

[ddeboer]

For example

• https://data.netwerkdigitaalerfgoed.nl/Anne-Frank-Stichting/Anne-Frank-Kennisbank: now valid
• https://data.netwerkdigitaalerfgoed.nl/coret/GoudaTimeMachine: same

See also #698, #352

[ddeboer]

Previously these datasets were invalid, but now they do pass validation. It looks like @TriplyDB has made some changes on their side to make this happen:

• DCAT is no longer included, which resolves Handle dcat:accessService #698.
• A license is included.

Unfortunately, this update does not seem to be available on all Triply instances. For example this one still has no license.

@coret Do you know more about this?

[coret]

The license is probably missing because the user hasn't defined a license for the dataset (this isn't required within TriplyDB).

I'll ask Triply about their datasetdescription improvements.

[ddeboer]

The license is probably missing because the user hasn't defined a license for the dataset (this isn't required within TriplyDB).

@coret will ask Triply whether license can be a required field.

[coret]

Will not be a required field.