Provide option to not auto-rotate logs

[ghost]

The automatic log rotation that winston currently does is counter-productive IMO: it's size-based (meaning there's no guaranteed retention time for log entries), it doesn't support compression, the knobs needed to tune the rotation parameters aren't exposed from gardener, and the whole feature duplicates functionality that's already present in tools like logrotate.

It'd be great if there was a way to turn off the log auto-rotation, so we could defer this to our existing logrotate setup.