Get official austintexas.gov email for ctxfloods

[Niicck]

Right now, we're using a gmail account for test and production emails. Aside from optics and credibility, there are actual dangers with using a gmail account for our application. A new deployment could trigger a "Suspicious Activity" flag within google and they can block emails from being sent. It's a cumbersome manual process to work around that:
https://stackoverflow.com/questions/13465269/suspicious-sign-in-prevented-heroku-amazon-aws-gmail-smtp