[bug 915560][bug 915559] Enable hu, sr-Cyrl, sr-Latn in AAQ/Support Forum.

Not sure when this needs to land, it's still up in the air. But I wanted to have it ready.

r?

To verify:
1) Make sure you can ask a question in each:
http://localhost:8000/hu/questions/new
http://localhost:8000/sr-Cyrl/questions/new
http://localhost:8000/sr-Latn/questions/new

2) The questions should show up in:
http://localhost:8000/hu/questions
http://localhost:8000/sr-Cyrl/questions
http://localhost:8000/sr-Latn/questions

3) The new locales should be listed here:
http://localhost:8000/en-US/questions/dashboard/metrics

The graphs will not work right until we get some data in and indexed.