Use proper logging instead of printing to stdoud

[Cito]

Separate more clearly and systematically which messages are printed to stdout and which to stderr, or even better: Make use of the logging module instead of conditional print statements with "debug" and "verbose" flags.

See also note on writing to standard output in the [mod_wsgi docs](https://modwsgi.readthedocs.io/en/develop/index.html].

Support configuration of logging output using Webware's existing support for config files.

Document how to do log rotation.

Also check whether we can make use of tools like Logbook to simplify logging.