Support Nested GraphQL Mutations

[sajeetharan]

Summary

This RFC outlines a proposal to implement support for nested Graphql Mutations.Nested mutations is the ability to perform mutations on a type other than the root type in GraphQL and how to define circular dependency schema files

Motivation

Most developers find it easier to think of "changes" in a sequential fashion. Databases can and do perform many update/insert/delete transactions concurrently. Any modern databases exposing any API (including GraphQL) has to be ready for concurrently arriving requests as well as nested mutations

Functional Specifications

Circular Reference

Nested Mutation Types

Referene

Nested mutations have been graphql/graphql-spec#252 but not yet approved

[aaronpowell]

Linking #906 as it has context on an outstanding bug that this poses

[aaronpowell]

https://hasura.io/docs/latest/schema/common-patterns/data-modeling/many-to-many/ is how Hasura exposes relationships (specifically many-to-many as that's the cause of #906) and could serve as inspiration for how the structures could be defined.

[aaronpowell]

This is probably a duplicate of #479