roles/named: Deploy BIND DNS server

The *named* role configures the BIND DNS server on managed nodes. It
writes `/etc/named.conf`, using a template that supports most of the
commonly-used options. The configuration can be augmented by other
templates, etc. by specifying file paths in the `named_options_include`
or `named_global_include` variables, both of which are lists.

roles/named/handlers/main.yml

@@ -0,0 +1,10 @@
+- name: restart named
+  service:
+    name=named
+    state=restarted
+- name: reload named
+  service:
+    name=named
+    state=reloaded
+- name: save firewalld configuration
+  command: firewall-cmd --runtime-to-permanent