Add the cyrus-frontend role

This role :
 - configure the cyrus-imapd service as a frontend IMAP
 - adds the murder configuration even if
 - adds the tls section in imapd.conf and the imaps and pop3s service in the cyrus.conf if we want to use the services over SSL
Add the cyrus-murder role

This role :
 - configure the cyrus-imapd service as a Aggregator IMAP (murder)
 - adds the murder configuration in the the cyrus.conf