turn adduser/download roles into meta roles

This should make things a little more composable,
by making these roles meta roles that perform no
actions by default we allow each role to own its own
resources.

roles/adduser/defaults/main.yml

@@ -0,0 +1,24 @@
+---
+addusers:
+  etcd:
+    name: etcd
+    comment: "Etcd user"
+    createhome: yes
+    home: "/var/lib/etcd"
+    system: yes
+    shell: /bin/nologin
+  kube:
+    name: kube
+    comment: "Kubernetes user"
+    shell: /sbin/nologin
+    system: yes
+    group: "{{ kube_cert_group }}"
+    createhome: no
+
+adduser:
+  name: "{{ user.name }}"
+  group: "{{ user.name|default(None) }}"
+  comment: "{{ user.comment|default(None) }}"
+  shell: "{{ user.shell|default(None) }}"
+  system: "{{ user.system|default(None) }}"
+  createhome: "{{ user.createhome|default(None) }}"