Add scraper for Department of State

This one took a bit, but ended up not looking that ugly in the end. Definitely a few weird edge cases though.

The biggest issue is probably the first two items in `BLACKLIST_REPORT_URLS`. I'm tempted to just hardcode the full report dictionaries for those.

Let me know if anything else looks wrong or doesn't make sense.

`./igs --only=state --dry_run --since=1990` passes for me.