Feature Request: Complexity Analysis

[brezal]

Examples from other libraries:

• https://async-graphql.github.io/async-graphql/en/depth_and_complexity.html

• https://hexdocs.pm/absinthe/complexity-analysis.html

[nalchevanidze]

Thanks @brezal, i think you should check #579.

there is described general pre-validation interface for morpheus. which i is easy to implement and users could use to write own complexity validation logic based on it.

or we could write server extensions package for it, since i don't think it should be in an app package.