Update Europeana endpoint and accomodate v2 API changes

[dravadhis]

Current Situation

1. The current integration of the Europeana API uses the https://www.europeana.eu/api/v2/search.json endpoint. However Europeana has changed it's API endpoint to https://api.europeana.eu/ to better manage traffic. This change has been noted in their API docs here. Corresponding change should be made in the present API integration script.
2. Some fields have been changed in v2 API. The backward compatibility of v1 API may be stopped anytime. Hence the API script needs to be modified according to the new fields. ( list of modified fields)
3. Above changes also need to be made in the test files wherever required.

Suggested Improvement

In the Europeana provider script, change value of ENDPOINT to https://api.europeana.eu/. Update the provider script and test suite with new fields according to v2 API. Ensure that the scripts run properly after making the changes.

Benefit

Currently the old endpoint is still working. However this might change. Accommodating above changes will ensure that Europeana integration is updated.

[zackkrida]

@WordPress/openverse-maintainers as far as I can tell the Europeana API is still backwards-compatible with the fields we are using. Is this GitHub issue the only reason our provider DAG for them is still disabled? Do we also need an API key? It would be nice to be able to run this while we await a contributor updating the script.

[stacimc]

@zackkrida I just checked and it looks like we are also missing an API key for Europeana. I'll make a ticket for that; once we have that I agree, we should let the script run as it does seem to be backwards compatible for now.

[AetherUnbound]

@sarayourfriend it looks like you actually closed this too in WordPress/openverse-catalog#821 😮 Is that correct?

https://github.com/WordPress/openverse-catalog/pull/821/files#diff-30cf1cf9d75f477a0be73d1f788cc9eff37480c1a884bb444f849dce71b75205R159

[sarayourfriend]

I copied the existing URL, didn't make any changes there: https://github.com/WordPress/openverse-catalog/pull/821/files#diff-30cf1cf9d75f477a0be73d1f788cc9eff37480c1a884bb444f849dce71b75205L33

[AetherUnbound]

D'oh, missed that! I didn't read this issue carefully enough either 🙂