Excessive Logging, Unable to Configure - Default Docker EXEC doesn't configure or allow logging customisation

[omad]

Background
DEA's Explorer deployment at the NCI has been periodically running out of disk space, and the only thing running on that VM is Explorer.

I've been looking at what Explorer is logging, and how to customise it. And, it's either impossible or very awkward.

There's a bunch of useful looking code in https://github.com/opendatacube/datacube-explorer/blob/develop/cubedash/logs.py#L13 , that customises the structlog configuration, but that never gets run when running with gunicorn like in the Dockerfile or K8s deployments.

They just use the structlog defaults, which aren't bad.... but, are quite verbose.

I think we should be able to customise the logging setup for production deployments.