Enhancement: Move to queryField and mutationField for generation and examples

[mthomps4]

Instead of creating one giant extendedType for Query
Opt to use nexus queryField and mutationField respectively.

https://nexusjs.org/docs/api/query-field
https://nexusjs.org/docs/api/mutation-field

Look to update user.ejs in our Graphql example
Look to update our graphql > new templates