Initial API Gateway setup

[briri]

Create the API Gateway and define the endpoints

• [x] Build out stub Lambdas for the following REST endpoints:
  • [x] GET /
  • [x] GET dmps/
  • [x] POST dmps/
  • [x] GET dmps/[:dmp_id] (determine if we can do content negotiation in the gateway ... which would mean we can have separate lambdas for each OR if we need to handle the negotiation in a single Lambda)
  • [x] PUT dmps/[:dmp_id]
  • [x] PUT dmps/[:dmp_id]/funding (define expected JSON input)
  • [x] PUT dmps/[:dmp_id]/related_identifier (define expected JSON input)
• [x] Build REST API Gateway and connect the endpoints to their corresponding Lambda functions
• [x] Add to CloudFormation template

[briri]

Done with initial setup. Will create a separate issue to review the CF config more thoroughly