Terraform module to deploy on Azure

[IamJeffG]

Goal

Resolve #30: demonstrate how to deploy on Azure

What I changed

1. Add new folder deploy/, containing terraform modules. This folder is added to .dockerignore, and also has its own Terraform-specific .gitignore
2. Terraform module relies on a bit of existing (most likely shared) infrastructure, namely a storage account and container registry. This can be specified by the user via Terraform variables.
3. Terraform module creates the Queue for new requests; the app container and its environment and scale-out rule.
4. README

What I'm not doing here

• Currently we do not address ways to share the Terraform state: that is, the mapping from resource names to actual deployed infrastructure. This might result in conflicts if multiple developers all try to manage the same deployment.
• No explicit way to manage the docker image version that's being deployed. Currently hard-coded to :test-3 label