title: Return annotated queryset against graphql queries on django graphene
body: <pre><code>class Project(models.Model):
      name = models.CharField(max_length=189)
  
  class Customer(models.Model):
      name = models.CharField(max_length=189)
      is_deleted = models.BooleanField(default=False)
      project = models.ForeignKey(Project, related_name="customers")
  
  class Message(models.Model):
      message = models.TextField()
      customer = models.ForeignKey(Customer, on_delete=models.CASCADE, related_name="messages")
      created_at = models.DateTimeField(auto_now_add=True)
  </code></pre>
  
  <p>I am using the following queryset to get all customers under a certain project ordered by who had messaged last.</p>
  
  <pre><code>qs = Customer.objects.filter(messages__isnull=False) \
  .annotate(last_message=Max('messages__created_at')).order_by('-last_message')
  </code></pre>
  
  <p>Now I want to use a basic graphene query (NOT relay) to get a project and the customers associated with this project according to the annotated queryset.
  I may also have a second use-case where I would need to filter the project.customers.all() queryset according to a field in the Customer table (e.g. the customers which have is_deleted=False).</p>
  
  <p>Currently in my graphql schema i have,</p>
  
  <pre><code>class ProjectNode(DjangoObjectType):
      class Meta:
          model = Project
  
  class CustomerNode(DjangoObjectType):
      class Meta:
          model = Customer
  
  class Query(graphene.ObjectType):
      project = graphene.Field(ProjectNode, id=graphene.Int(), token=graphene.String(), )
      top_chat_customers = graphene.Field(CustomerNode, project_id=graphene.Int())
  
       def resolve_project(self, info, **kwargs):
          pk = kwargs["id"]
          return Project.objects.filter(id=pk).first()
  
      def resolve_top_chat_customers(self, info, **kwargs):
          project = Project.objects.filter(id=kwargs["project_id"]).first()
          return Customer.objects.filter(project=project, messages__isnull=False) \
  .annotate(last_message=Max('messages__created_at')).order_by('-last_message')
  </code></pre>
  
  <p>Here when I try to get the list of customers separately by providing the project Id, It shows error: "Received incompatible instance..."</p>
  
  <p>Any ideas on how I should get the list of customers from within the project node and as a separate top_chat_customers query?</p>
  
  <p>Any help is appreciated. Thanks!</p>