Add support for json out from schema

[veritem]

Currently schema only generates .gql file only, if there was a way to generate .json schema it would be aplus

[santialbo]

makeSchema takes an optional customPrintSchemaFn which you could probably use to print json instead with your library of choice.

[veritem]

@santialbo I ended up using codegen not sure how that works

[santialbo]

That's another option, I also use graphql codegen on my project

[veritem]

codegen seems to be a good option for this but I would love to have it built into nexus