Add support for non-relational databases

[OpenDataAlex]

Need to provide some options for working with non-relational databases. Requires some research as to which to support.

[OpenDataAlex]

The more I think about it, the less I like the idea of something that really needs referential integrity and strong transactional support trying to use a non-relational data store. I'll keep thinking on it because I don't want to exclude the possibility, but I'm starting to lean into the 'not going to happen' camp.