Looking up versions of storage manifests is very inefficient (and possibly broken for C&D)

[alexwlchan]

There's an API to get all the versions of a storage manifest, which:

• Looks up all the versions in DynamoDB
• Goes and opens every storage manifest that's listed

This is because we include the creation date of the manifest in the API response, but that's only stored in the S3 object and not in DynamoDB. We should consider if there's a better way to store/present a list of versions – possibly by storing the creation date metadata in DynamoDB.

I suspect looking it up will actually just fail for C&D, but I didn't wait around to find out.

[C&D = Chemist & Druggist, a bag with a very large storage manifest. See https://docs.wellcomecollection.org/storage-service/wellcome-specific-information/awkward-files-and-bags]