feat: rewrite abstract fragments for grpc#1268

ysmolski merged 7 commits intomasterwundergraph/graphql-go-tools:masterfrom

yury/eng-7487-enforce-rewriting-abstract-fragments-for-grpc-datasourcewundergraph/graphql-go-tools:yury/eng-7487-enforce-rewriting-abstract-fragments-for-grpc-datasourceCopy head branch name to clipboard