add support for unregistration

Since the big refactor we have lost the ability to unregister nodes
on scale down / delete.

This patch provides the framework for this, and will be followed
by a later patch which implements unregisteration as above.

Change-Id: I02c5c18f710172b2b988067c020551e3f58c392d

tasks/main.yml

@@ -22,3 +22,4 @@
     - rhsm_register
     - rhsm_repos
     - rhsm_satellite
+    - rhsm_unregister

tasks/unregister.yml

@@ -0,0 +1,12 @@
+- name: Unregister Red Hat subscription
+  redhat_subscription:
+    username: "{{ rhsm_username | default(omit) }}"
+    password: "{{ rhsm_password | default(omit) }}"
+    activationkey: "{{ rhsm_activation_key | default(omit) }}"
+    org_id: "{{ rhsm_org_id | default(omit) }}"
+    pool_ids: "{{ rhsm_pool_ids | default(omit) }}"
+    state: "absent"
+    rhsm_baseurl: "{{ rhsm_baseurl | default(omit) }}"
+  register: subscrition_result
+  tags:
+    - rhsm_unregister