Remove ufw role

Ansible has a ufw module for manaing rules more easily. This role may be
re-added later on that adds rules based on host/group vars but as is
this role is obsolete.
Update sensu uchiwa variables

Allows variables to change the uchiwa username, password, host and port.
Add default sensu check for NTP
Update powerdns variables

Allows overriding of powerdns defaults and adds in listening interfaces
as a list