DSL compiler for `GraphQL::Schema::ObjectType`

When using field in GraphQL object types, new methods are created in the class dynamically. In certain occasions, like in batch loading, we need to be able to refer to those methods and avoid type checking errors.

class MyType < GraphQL::Schema::Object
  field "foo", type: String

  class << self
    extend T::Sig

    sig { params(objects: T::Array[MyType]).void }
    def load_foo(objects)
      objects.each { |obj| obj.foo = "hello!" }
                              # ^ error: foo doesn't exist on MyType
    end
  end
end

Start with the GraphQL::Schema::Object example in the issue and inspect how Tapioca currently handles DSL compilers. Determine how dynamically defined field methods should be represented for Sorbet, then verify that batch-loading code can refer to obj.foo without a type error.