Refactor package names to match module names

[Tom Zeller]

> Certainly in principle yes. I think the session stuff is going to want to
> end up in its own module, but I'm not sure yet. For now I'd just leave it
> until we have working code and I can adjust it then or as I work it out.
>
> Also not sure about the relying party piece. Doesn't feel 100% like a
> profile thing to me, at least not exclusively, but for now probably fine.

Okay, seems reasonable.