Debug logs written to stderr

[jnorkus]

Describe the bug
Debug logs are written to stderr, which causes them to appear as errors in Google Cloud.

Expected behavior
Only errors should go to stderr. Even better, that should be configurable.

Additional context
After some digging I found out that the version of Winston currently used has this default setting:

stderrLevels: { error: true, debug: true }

Latest version of Winston defaults to nothing being written to stderr:

stderrLevels: {}

My suggestion is to add a stderrLevels logger setting in pelias.config. I can submit a PR.

References

Upgrade to Winston 3 issue