Use Django Rest Framework's native implementation of OpenAPI schema

[helrond]

Is your feature request related to a problem? Please describe.

As of version 3.10, Django Rest Framework now supports generation of OpenAPI schema. Using this built-in version would allow us to shed several dependencies, some of which are not well-maintained.

Describe the solution you'd like

Replace existing OpenAPI view and endpoint with DRF's implementation.

Additional context

See [https://github.com/RockefellerArchiveCenter/argo/blob/master/api_formatter/urls.py] for implementation of DRF OpenAPI schema.