Show DOIs for published datasets

[sbliven]

Summary

For published datasets there should be a link from the dataset to any DOIs. This mapping is stored in the published-dataset schema, but not included in the dataset pages.

Expected Behaviour

I could see this included either on the Dataset 'Details' tab or on the 'Related Datasets' tab. I think the DOI should have some prominence, so adding it to 'Details' might be better. The Details tab also has a switch for the Dataset.isPublished field, which I would expect to be synchronized with the DOI state for sites that assign DOIs.

Extra Details

• Datasets can belong to multiple DOIs
• We might need to add a mongodb index across PublishedDataset.pidArray for performance