Review ingest state

[bjchambers]

Think about what information we want for ingestion states and how we want to reflect that. Especially as we may end up with multiple versions of documents in different states, etc.

          Do we want a separate ingest state for "ingesting" (so we can determine whether we have a URL / content hat we're working on)? Right now, I don't think we *need* it since we can say:

1. When we receive new content, we try to ingest it.
2. When we ingest new content, we update the document.
3. We can use transactions to make sure only the final update wins.

But, I suspect we'll want some way of recording what "upload" we're doing so we can make things idempotent. But I don't think we need that in the state (we could have the "upload" take a version as well, so that it only lets the upload proceed if the document version is as expected).

Originally posted by @bjchambers in https://github.com/DewyKB/dewy/pull/82#discussion_r1488572625

[bjchambers]

@kerinin add details when you get a chance? we can discuss