Enable logging.conf & fluentd for keystone

This change introduce ability to use log_config_append parameter with
new FluentdHandler to send logs directly to Fluentd.

To save per binary log streams as it is in the default logging states generates
separate logging.conf files per service and use /etc/default/<service name>
to pass dedicated logging.conf to every service.

Change-Id: I420dd20c2ba7017a2ed336361da1a684d93a77ed
Related-Prod: PROD-16324
14 files changed