ansible: Install Ansible

The `ansible.yml` playbook and corresponding *ansible* role simply
install Ansible and related utilities, such as OpenSSH and GnuPG.

ansible.yml

@@ -0,0 +1,3 @@
+- hosts: ansible
+  roles:
+  - ansible

hosts

@@ -29,3 +29,5 @@ dch-gw
 dch-gw
 
 [jenkins-slave]
+
+[ansible]

roles/ansible/tasks/main.yml

@@ -0,0 +1,4 @@
+- name: ensure packages are installed
+  package:
+    name=ansible,gnupg,openssh-clients
+    state=present