Built-in GraphQL support

[nickroberts]

It would be great if this worked out of the box with Craft's new built-in GraphQL support.

Currently, fields are not returning correctly. e.g. a custom phoneNumber field that is a Sprout Phone Number field is being returned as a string, and not the object it should be.

We would like to use the built-in GraphQL solution, so we are no longer dependent on the CraftQL plugin (which we used its third-party fields support for Sprout Fields).

[BenParizek]

Thanks @nickroberts. This is on our list.

We're a bit busy this month but we'll be sure to update this ticket once we add support.

[nickroberts]

Looking forward to it!

For reference, here is a reference to an issue in Craft: craftcms/cms#5067

[BenParizek]

PR for review here: #96