Allow logging to a file from the CLI

[brianthelion]

Problem

Shell-based redirection isn't always an option when one needs to log kopf output to the filesystem.

Proposal

kopf run should provide an option to log to a file from the CLI.

Alternatively, kopf could provide a more comprehensive API for logging configuration, so that such configuration could be performed in an @kopf.startup handler.

Code

kopf run ... --log-file=controller.log

Additional information

No response