Add Tutorial with Example Terraform Setup and API calls to Granary

[Chris Brown]

We should document how users can add an AWS batch model to granary.

It should describe the following:

• Overview of Granary execution model and role in model running
• Terraform setup to create resources in batch to run a model - including using the public water example, arguments, etc
• Sample API calls using curl for adding the model
• Explanation of how permissions work with respect to AWS and granary