[bug 1063825] Integrate spicedham into fjord

* add required spicedham backend
* add trainabuse command for training the tables
* add docs for maintaining the training data
* add some tests
* update spicedham to a version that has some fixes we needed

After this commit, everything is hooked up except the initial training
data. That'll be in a later commit.
Nix "spam" and "spam-wrong" flags

We're only going to be classifying "abuse" during the prototype
integration with spicedham. We'll look at classifying "spam" in a later
phase.
Ignore bin/update/update.py for flake8 pass

This is the deploy script that we "share-ish" with other groups, so if
we lint it, that makes it harder for them to take changes back.
Merge pull request #346 from willkg/1063825-spicedham-backend

1063825 spicedham backend