Facilitate graphql monitoring with playground on Nest.js

[chargome]

While debugging an issue I just realized that tracing for graphql on nest with activated playground created lots of noise in performance, making it hard to find actual queries/mutations to /graphql. I thing the reason is that the graphql playground sends introspection queries every few seconds.

DX could be improved by dropping these transactions (maybe with a config flag?).

Here's a repo to get started: https://github.com/chargome/ex.nest-gql

After spinning up the server just visit http://localhost:3000/graphql and run a simple query (query Foo{hello}).