Support logging to GCP directly

[jlewi]

We want to support the following logging configurations

• Emitting logs to stdout/stderr in non-JSON format
  • This is useful when running locally and the logs are directly consumed by humands
• Emitting logs to stdout/stderr in JSON format
  • This is useful when running on K8s and we want to emit structured logs that are automatically collected
• Emitting human logs to stdout and JSON logs directly to Cloud Logging
  • Useful when running locally and we want to stream logs to Cloud Logging for better analysis.

This requires refactoring the logger so we can setup separate cores; one for the console and one for the json logger. We can then use a tee to log to both of them.

• build command should use the logging configuration