Add rotate file handler to default settings

[nitely]

And put it in order: "console", "file", "mail_admins" (coz if there's an error with email then file never get logged). Make it max 1 (or 2 if 1 is not allowed) file of 10MB or so.

[nitely]

See if there is a way to log deprecation warnings (just deprecations) for Spirit. Add level error to the email handler, to void user mistakes.

        'mail_admins': {
            'class': 'django.utils.log.AdminEmailHandler',
            'filters': ['require_debug_false'],
            'level': 'ERROR',
        },