Decide on logging behaviour for the server and worker client code

Proposal:

• client logging must exit non-zero on error and zero on success
• client logging to use standard behaviour of errors and warnings to stderr, info and debug to stdout.
• server logging needs to be collated using logrotate, timestamped in UTC and use the Python logging module
• Options to change the logging level on the server, actionable at runtime - preferably without needing to restart the server, the django uwsgi/gunicorn process or any other running process.
• Same logging patterns used for all parts of the server reporting
• Options to send some logging output to separate files, based on functionality and logging level.