SPIKE: rendering of openapi definitions

[dogversioning]

Both the aggregator and the dashboard are producing openAPI 3.0 specs for documenting the expected behavior of the endpoints they provide. It would be nice for the docsite to present these in a graphical way with off the shelf tools, so that we don't need to regenerate artifacts on change.

There are a few options
https://github.com/jonasob/the-open-api - this jekyll plugin is a lightweight version that does not provide the interactive 'test out a http request' mode, which is probably not what we're looking to do with our documentation anyway
https://www.npmjs.com/package/openapi-to-md - this would allow us to just render openapi docs as markdown, which would work well when viewed in github as well
https://swagger.io/tools/swagger-ui/ - there are docker images of the swagger UI available that we could spin up/redirect to

The goal here would be a single documentation rendering approach that would apply for any existing, or future, APIs we develop as part of Cumulus.

[dogversioning]

@vlad-ignatov this is trying to capture the discussion from yesterday - feel free to add notes/other proposals.