feat(parser): add inline graphql support

[gorillamoe]

Enable inline graphql support.

This here should work now.. haven't tested mutations, yet, but they should also work..

with variables:

# @graphql 1
POST https://swapi-graphql.netlify.app/.netlify/functions/index HTTP/1.1
accept: application/json

query Person($id: ID) {
  person(personID: $id) {
    name
  }
}
variables { "id": 1 }

without variables:

# @graphql 1
POST https://swapi-graphql.netlify.app/.netlify/functions/index HTTP/1.1
accept: application/json

query Query {
  allFilms {
    films {
      title
      director
      releaseDate
      speciesConnection {
        species {
          name
          classification
          homeworld {
            name
          }
        }
      }
    }
  }
}

closes #58