Add functionality to easily integrate with Dataloaders

[lytedev]

Many of the points in issue #15 apply here as well.

At the moment, [Dataloader][dataloader]s are a popular way to batch up Absinthe resolvers. This naturally hides a lot of the traceability by foregoing the default absinthe pipeline.

Perhaps a Dataloader that is a simple layer over the default dataloader that can either simply be used instead of the default or that provides simple functions to integrate with existing dataloaders.