Right now Private Aggregation monkey patches us a lot to implement
our integration. This moves over the most mundane of the changes ---
parsing of new IG and AuctionConfig fields --- to reduce the size of
the monkeypatch and to practive how the process works.

It's moved basically unchanged (except different indent/wrapping);
I think the only substantative change is using our origin parser.

https://github.com/morlovich/private-aggregation-api/tree/move-stuff-to-pa
has the other half, it likely needs something with imports (I hope
adding export to auction config/interest group on our end will help).