GraphQL bindings.

Inspired by `mockServer` in [GraphQL tools](https://github.com/apollographql/graphql-tools), create GraphQL bindings for Kitimat. Given a `schema.json` and a query, I should create a generator.

```ts
import { fromGraphQL } from 'kitimat-graphql';
improt schema from './schema.json';

const server = fromGraphQL(schema);

const queryGen = server(`query {
me {
id
name
}
}`);

check('my component renders', queryGen, result => {
// ...
});
```

I'm already squating `kitimat-graphql` in packages.

Start by reading the GraphQL tools `mockServer` reference and inspect the planned `packages` area for `kitimat-graphql`. Trace the proposed `fromGraphQL(schema)` entry point and its query-generator usage with `schema.json`. Done means a schema and query can produce the generator shown in the example, with the component check receiving the generated result.

Written by the indexing model from the issue text.