Allow integration with loggers (pino and other) for ability to aggregate all Keystone output in structured mode

[MurzNN]

Now Keystone simply outputs the log lines into stdout via console.log that makes it hard to integrate with modern logging libraries like Pino, Winston, Bunyan, npmlog, etc.

To allow the integration we can simply create a middleware library logger, that by default just do the same thing - console.log('string') but allow replacing it by any custom external library to give flexible log aggregation ability. What do you think about this idea?

[MurzNN]

Here are example of logs from Keystone in plaintext, that good to have in JSON format:

✨ Starting Keystone
✨ Connecting to the database
✨ Creating server
✅ GraphQL API ready
✨ Preparing Admin UI Next.js app
{"level":30,"time":1657622287549,"pid":28,"hostname":"my-keystone-5978b76984-czvzv","category":"system","operation":"init","msg":"Keystone is initialized."}
✅ Admin UI ready
⭐️ Server Ready on http://localhost:3000
An error occurred handling a request for the Admin UI: TypeError [ERR_INVALID_URL]: Invalid URL: anonymousfox.co
    at new NodeError (internal/errors.js:322:7)
    at onParseError (internal/url.js:270:9)
    at new URL (internal/url.js:346:5)
    at Object.isAccessAllowed (/app/.keystone/admin/.next/server/pages/api/__keystone_api_build.js:9196:94)
    at /app/keystone_core/packages/keystone/dist/createAdminUIMiddleware-ccfdeb37.cjs.dev.js:177:92
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:95:5) {
  input: 'anonymousfox.co',
  code: 'ERR_INVALID_URL'
}

And only in line 5 there is a custom log record, generated through a 'Pino' logger.

[rachmanov]

+1, very useful feature

[dagual]

A good idea. The feature will greatly facilitate the support and control of applications.

[fmquaglia]

It is a critical feature for running Keystone in major cloud providers. We're deploying this using Google App Engine, which creates a container inside a managed instance.
When the container crashes for an unexpected error, we're not able to gather the logs, because user containers' logs are only accessible if using Winston or Bunyan.