Refactor to simpler backend

[vsoch]

I haven't been happy with the constantly changing fastapi / starlette / pydantic interface - having worked with flask/django for over a decade I have never hit the sheer number of issues with just getting dependencies installed in many years as I have in just one here. I think this library needs a total overhaul - likely (since we have most of the Python plumbing here) I'll maintain a Python version, but I think a better solution would be a go-based one. I don't know when I'll make time to do these (now two projects) but for the time being I'm removing it from the flux operator because it's simply not good enough.