Remove standalone etcd specific play, cleanup host mode

Now etcd role can optionally disable etcd cluster setup for faster
deployment when it is combined with etcd role.

roles/etcd/tasks/install_host.yml

@@ -1,9 +0,0 @@
----
-- name: Install | Copy etcd binary from downloaddir
-  command: rsync -piu "{{ etcd_bin_dir }}/etcd" "{{ bin_dir }}/etcd"
-  register: etcd_copy
-  changed_when: false
-
-- name: Install | Copy etcdctl binary from downloaddir
-  command: rsync -piu "{{ etcd_bin_dir }}/etcdctl" "{{ bin_dir }}/etcdctl"
-  changed_when: false