OpenAPI spec implementation

[jbrown-xentity]

User Story

In order to have a well documented API, data.gov admins want an OpenAPI spec document describing the Flask API for harvesting.

Acceptance Criteria

[ACs should be clearly demoable/verifiable whenever possible. Try specifying them using BDD.]

• GIVEN an OpenAPI spec document is complete
  WHEN I go to https://authress-engineering.github.io/openapi-explorer/?#?route=post-/echo and put in the raw link for the spec file
  THEN the API is usable and explorable \

Background

Some of our routes are already defined, but the code should be the final decider of what is implemented (and use tests where possible).
https://docs.google.com/document/d/1XQFmHDtpCEPwM1JsvgOmeKKmxcUwr7EvP4EWowWnq6U/edit#bookmark=id.s20mfruog1ta

Security Considerations (required)

None

Sketch

There are many tools to create and manage this spec file. I would start with the generators, but feel free to explore further.