Add VerifiablePresentationResponse with property verifiablePresentation

[aljones15]

Responses from the continue endpoint should be VPs.

NOTE: This PR began as a simple feature request: add verifiablePresentation as property in the request/response for exchange continue. This turned out to be a bigger task than anticipated as it required adding response bodies to responses. This Pr handles that, but refactoring of the underlying code remains and eslint has also shown issues with the respec-oas.js reporter that probably need to be addressed in another PR.

Addresses: #311

Features:

1. The response table now has a new section body
2. Response bodies are shown as summaries
3. renderJsonSchemaObject can now handle anyOf
4. Some functions in the reporter were trimmed and helper functions were created out of existing code
5. eslint and eslint-config-digitalbazaar were added to the project

[TallTed]

My reviews are of limited value. You should re-request the reviews from @msporny, @peacekeeper, @mavarley, and @mkhraisha.

[aljones15]

My reviews are of limited value. You should re-request the reviews from @msporny, @peacekeeper, @mavarley, and @mkhraisha.

your review was valuable, but I don't have the ability to request more reviewers. Anyways, thanks for your comments.