💡Allow logging to stdout instead of stderr

**Describe the feature you'd like**
I would like for cloudflared to log to stdout instead of stderr

**Describe alternatives you've considered**
Redirect them manually, however, this is not possible in the container as those do not include any shells which would enable redirection

**Additional context**
When output is send to stderr many things assume they are errors, like kubernetes or systemd, see last comment of #296