Move blockIp and blockEmail to SQS messages (fix #27)

Ah, cool.  FWIW it's possible to intuit the "current region" from an instance's metadata, e.g. the tokenserver sqs script does it like this: https://github.com/mozilla-services/tokenserver/blob/master/tokenserver/scripts/process_account_deletions.py#L51

But maybe not worth it for the sake of saving one config value.