Switch to using R53 instead of IP addresses

[Josh Mottaz]

Route53 seems like a much better solution for allowing routing to the server, instead of having to have an elastic IP sitting around.

Using only a hosted subdomain, rather than a full hosted zone: https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/CreatingNewSubdomain.html#AddNewSubdomainRecords
Routing traffic to an EC2 instance: https://github.com/awsdocs/amazon-route53-docs/blob/master/doc_source/routing-to-ec2-instance.md

1. Create a R53 hosted zone for the domain (or subdomain).
2. Add NS records for each of the four nameservers.
3. Each time an instance spins up, it should add an A record to the hosted zone with the instance's public IP.

[Josh Mottaz]

Fixed in #17.