Configure a fully qualified domain name (FQDN)

**ISSUE**
We need to be able to retrieve both the domain and the hostname
for the server

**SOLUTION**
Assume that the domain name used when building the server will also
be the externally resolvable DNS domain for the server.  Use
that domain to configure a FQDN via the `hostname` directive.

roles/set_hostname/tasks/main.yml

@@ -10,7 +10,7 @@
 
 - name: Set hostname
   become: yes
-  hostname: name={{ hostname }}
+  hostname: name={{ [hostname, domain] | join('.') }}
 
 - name: Edit /etc/hosts
   become: yes