fix(contrib/ec2): add custom template

While CoreOS's default template is great for setting up a cluster
on CloudFormation, it's missing some custom security group rules
that Deis needs. This custom template is a copy of CoreOS's
template along with a few ports opened, which includes the ports
that the Deis components live on as well as linux's default
ephemeral port range, which docker relies on (as well as any
Deis apps)