Investigate the openapi-generator

[https://openapi-generator.tech/](https://openapi-generator.tech/)
After #48 is merged, investigate how we can use the `openapi.yaml` file to generate code with openapi-generator in this and in future projects, including:

- generating client-side functions to call the endpoints with axios (used by React/next)
- generating abstract classes/interfaces for serverside boilerplate code (used by nest.js)
- generating Postman collection

After #48 is merged, start by reading openapi.yaml and the OpenAPI Generator documentation. Investigate approaches for generating axios client functions for React/Next projects, abstract server-side classes or interfaces for Nest.js, and a Postman collection; done means documenting viable generation options for this and future projects.

Written by the indexing model from the issue text.