Get rid of checked-in copy of graphql-js

[lastmjs]

Right now I've included a copy of https://github.com/graphql/graphql-js in this repo, because I needed to modify the paths of the ES module imports, because Zwitterion does not deal with implicit index.js files. Once Zwitterion is fixed, get rid of the local copy throughout the entire repository history. Also, the Node.js version of ES modules is being used just for iterall...so it is not a relative path. Hopefully Node.js just gets rid of that, but if not, we'll have to figure that one out still.

[lastmjs]

Perhaps we must admit defeat and use a bundler like Parcel, because even when all code is written in ES modules, Node.js code is going to use paths that aren't paths at all, and rely on metadata in package.json to find where modules' entry points are. This will require a bundler to use on the front end

[lastmjs]

Ignore the above comment, I'm going to hope for some bare imports to be allowed in the browser someday, and I'll update Zwitterion to cope: lastmjs/zwitterion#100