* Replace apivore api tests with rswag
* move to OpenAPI Spec 3.0.1
* a swagger UI is now reachable at http://localhost:3000/api-docs/index.html
* swagger file is generated by running `RAILS_ENV=test rails rswag`
and it was moved from /docs/swagger.v1.yml to /swagger/v1/swagger.yml
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Co-authored-by: viehlieb <pf@pragma-shift.net>