364 logging

This adds some configuration for logging. The default configuration can be found in django/utils/log.py.

I am not completely happy about this solution.

• I am not sure where the logfiles should be located. Our code BASE_DIR might not be writable.
• I am not sure about the format. I found the Common Log Format but it does not seem to be suitable for our case. Does anyone have experience with this?
• I am not sure about the word "audit" as root for everything we log for monitoring user behavior.
• There does not seem to be a catch-all to log all warnings and errors to the logfile.
• The configuration is complicated, party because I tried to make it work for both development and production. (e.g. django.server is not used in production). Should we write logfiles only in production?
• It does not seem to be possible to simply add a logger to the configuration (src)