Add a devel tab for JSON:API

Problem/Motivation

When working with JSON:API, I often need to look at the JSON:API version of an entity. However, getting the URL for this is a tedious process:

1. Load the entity's page
2. Go to the devel tab for the entity
3. Find the UUID field and copy its value
4. Assemble the JSON:API URL in the browser address bar

It would be nice to have a tab showing JSON:API output

Proposed resolution

(Description of the proposed solution, the rationale behind it, and any workarounds)