dev -> main. Schema changes; switch to flask-only; multi-label model

[andylolz]

This merges dev into main, which includes lots of fixes:

Fixes #20. Fixes #21. Fixes #23. Refs #42 (makes progress on this one, but possibly we should keep it open because this doesn’t exactly address it). Fixes #62. Fixes #66. Fixes #71. Fixes #77.

With #76 included in here, this also:

Fixes #61. Fixes #70.

---

How to deploy

1. merge this branch
2. checkout main and pull
3. the nginx_docker ansible playbook will need to be run, because this PR includes nginx changes. Instructions in the README
4. delete the database
5. run the deployment workflow on the main branch

I think that should do the trick?

---

Pull request checklist

• [x] I have linked my PR to an issue
• [x] I’ve used conventional commits
• [x] My branch is up-to-date with main
• [ ] Where appropriate, I have added or updated tests
• [x] Where appropriate, I have updated documentation to reflect my changes

[ff-dh]

I think this is ready to approve?

[andylolz]

I think this is ready to approve?

All the things raised so far are hopefully addressed. If you’re happy then I’m happy!

[dcorney]

I'm also happy for this to be merged! I haven't had time to do a line-by-line review, but the dev branch has been working locally, and I can't see anything here that would break it. Let us merge!

[andylolz]

Amazing – thanks both 🎉