Generate Elixir API from Swagger / OpenAPI 3.0

To give some perspective. It is also difficult to keep this in sync with the openapi spec over time. Also, the generators get old very fast. From my experience from using this in java. We had more trouble with the generator. Instead, we built it manually and programmed unit tests to check that the implementation is in sync with the openapi spec.

And also the spec is quite complex as this is using all features json-schema has to offer.