Make status of sources clear

[sdevalk]

Some terminology sources in the NoT are not being maintained actively. The sources are stil usable, but it would be helpful to make clear what the status of the sources is. Users can then decide whether or not they want to use them.

We could add a status indicator to our dataset descriptions. Perhaps there's a specific vocabulary that we can use for this. Alternatively, we could add the status to e.g. a schema:usageInfo property or to the current schema:description.

[EnnoMeijers]

This would also be useful for stating the update policy of a source if there is any. For example the KB has currently a quarterly update interval for the NTA.

[ddeboer]

There’s also https://schema.org/creativeWorkStatus