Extend Dataset and File use cases: add privateUrlToken #470

There are several api endpoints that take a query parameter for the privateUrlToken. We need to update them to update the Dataset and File page to support privateUrls.
For example:
GET /api/access/datafile/{fileId}?key={privateUrlToken}
GET /api/access/datafile/{fileId}?imageThumb=true&key={privateUrlToken}
GET /api/access/datafile/{fileId}?format=original&key={privateUrlToken}
GET /api/access/datafiles/{fileIds}?key={privateUrlToken}
GET /api/access/dataset/{datasetId}/versions/:draft?key={privateUrlToken}

GET /api/v1/datasets/{id}?key={privateUrlToken}
GET /api/v1/datasets/{id}/versions/:draft?key={privateUrlToken}
GET /api/v1/datasets/{id}/versions/:draft/files?key={privateUrlToken}
GET /api/v1/datasets/{id}/versions/:draft/files/counts?key={privateUrlToken}
GET /api/v1/datasets/{id}/versions/:draft/downloadsize?key={privateUrlToken}
GET /api/v1/datasets/{id}/versions/:draft/metadata?key={privateUrlToken}