Generate markdown files from json schemas at build time

[jciruolo]

Is your feature request related to a problem? Please describe.
Keeping markdown files in sync with json schema specs manually is time-consuming and error-prone, we should be able to generate our schema documentation (at least) from the files we're already validating against.

Describe the solution you'd like
Investigate using https://github.com/adobe/jsonschema2md as it supports jsonSchema v7 (also compatible with ajv).