Support idle culler debug logging

[manics]

trafficstars

Proposed change

The Z2jh idle culler does not support debug logging: https://github.com/jupyterhub/zero-to-jupyterhub-k8s/blob/b407b541b1ee2a0f699e90699b61c2299c460547/jupyterhub/files/hub/jupyterhub_config.py#L356-L391

For instance, it should be possible to enable debug logs using Tornado's built-in option --logging=debug, which could be passed when debug.enabled is set in the chart.

I noticed this whilst answering https://discourse.jupyter.org/t/idle-culler-not-culling/21301/3

Alternative options

• Add a new option to control idle culler logging
• Allowing an array of additional command line args to be passed
• Allow the entire idle culler command to be overridden

Who would use this feature?

Admins wanting to debug the culling in z2jh.

(Optional): Suggest a solution

See above