Deploy cluster via AWS CloudFormation template

Running the cluster via the Vagrant EC2 provider has been verified to work just fine, see #18 - however, for production scenarios the provider is currently lacking all sorts of features (ranging from basics like Elastic IP address assignment to advanced ones like e.g. support for AutoScaling and EC2 spot instances etc.), which would need to be either implemented upstream or scripted locally and basically reinvent what's available in [AWS CloudFormation](http://aws.amazon.com/cloudformation/) anyway.

Therefore a CloudFormation based deployment seems to be a more suitable starting point for (semi-)automated deployment orchestration from Jenkins and/or Nolio (not the least because this has been used successfully for a couple of similar cluster scenarios already).

Ideally the existing provisioning script(s) can simply be reused via the CloudFormation [Cloud-Init](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cloudformation-waitcondition-article.html) mechanism with a few modifications only.