Replace sbom/advisory upload API's with a single doc upload API

[jcrossley3]

When uploading docs through the UI, I was bothered by it forcing me to choose whether I was uploading an SBOM or an Advisory. This puts an unnecessary burden on the user. We should accept whatever doc they give us and ingest it if we can.

We already have the capability to detect doc formats, but our API for uploading docs predates that ability: it forces the caller to know whether they're uploading an sbom or an advisory.

I think we should simplify the API (reduce the two fn's to a single one) thereby simplifying the UI and hence enhancing the user experience.