Update 'ansible' role

- 'ansible' role now detects installed Redis on Ansible Controller
  and sets up host fact caching automatically;

- tasks which run test integration and mail the results have been
  removed;

- added configuration of /etc/ansible/ansible.cfg from a template;
Add alias 'monitoring@' in Postfix

'monitoring@' alias should be used as a mail recipient for messages from
monitoring services like Monit, Nagios, etc. It is aliased to 'root'
account by default, but can be easily modified per group or per host.
Merge pull request #132 from drybjed/bugfixes

Updated 'ansible' role, added 'monitoring@' mail alias