Investigate with swift-openapi-generator

[LePips]

Purely as an investigation, check out a generation with:

• https://github.com/apple/swift-openapi-generator

CreateAPI has been great, especially since I learned a lot when I contributed to it, but the people who now have control over it no longer maintain it. Alternatively, I may look at using my own fork that would have additional work.