graphql.js spec importer

These specs have been generated from the testsuite in graphql/graph-js.

Direct modifications should not be made to most of this directory, instead take a look at the exporter.

# update to latest
$ rm graphql-js-commit.log && ./export.sh

# re-generate with known revision
$ ./export.sh

You will then need to manually update the validator/prelude.graphql file, validator/schema.go file, and possibly other files relevant to those specific changes like ./validator/rules/, etc.

Please in your PR description note the git release tag that corresponds to the graphql-js commit.