Provide Examples to overwrite generated schema

[jawosis]

Assuming nexus is already used in production there must be some examples of how to overwrite a schema generated by nexus/schema to allow:

• using annotations, e.g. @cacheControl with apollo server
• transform types, e.g. with gintonic

When using t.crud(), there seems to be no other solution to control projected fields and types other than completely overwriting the resolvers and types which makes the t.crud() feature not very helpful.