Define data access layer

[athompson-r7]

We need to get something in place that will allow us to swap between direct communication with cloudformation and our own storage layer.

[erran-r7]

@athompson-r7 @jmanero-r7 @bcall-r7 @bturner-r7 @eciramella-r7 Thoughts on the need of a storage layer? We have a non-persistent level of storage. I'm assuming the storage we refer to in this issue would be more similar to Terraform's execution plan concept.

[athompson-r7]

We might want to close this. I don't have a clue what the intent here was :/

I assume it had something to do with some caching service.