Stepfunction Event logger TODO

[leothomas]

Next steps for the stepfunction event logger, in decreasing order of priority (and complexity):

• Add CDK code here, to spin up necessary Postgres infrastructure if the user selects the POSTGRES datastore options
• Add python code here to format and send stepfunction history items to Postgres datastore
• Add unit tests + integration tests for the lambda function
• Implement user-configurable DynamoDB indexes and capacity scaling (to allow user finer grain control over the most cost intensive aspects of the seed)