Use include/import tasks (#2192)

import_tasks will consume far less memory, so it should be
used whenever it is compatible.

roles/etcd/tasks/configure.yml

@@ -30,7 +30,7 @@
   notify: restart etcd
 
 - name: Configure | Join member(s) to cluster one at a time
-  include: join_member.yml
+  include_tasks: join_member.yml
   vars:
     target_node: "{{ item }}"
   loop_control: