Migrate netlify build previews config to repo

[Relequestual]

Any idea why the deploy preview doesn't include the PDF?

I don't know how the Netlify build works, but I know that getting all the LaTeX dependencies installed was what was needed to get the PDF to build (and to fix other build issues) when I setup builds with docker.

It looks like I manually set the build command and resulting build location in the Netlify UI.

It can be set using a config file, but that shouldn't block this PR.

I'll make a new issue (https://docs.netlify.com/configure-builds/file-based-configuration/)

Originally posted by @Relequestual in https://github.com/json-schema-org/understanding-json-schema/issues/164#issuecomment-871217803