group_vars: Refactor installer/kubespray

This change refactors kubespray installer playbooks and
roles to use group_vars instead of using vars from
engine/engine/var directory.

The inventory file necessary for stack installation is
now used from engine/engine/inventory/inventory.ini in
order to utilize group_vars. Includes for the previous
vars files have been removed.

See the first change in series for the reasoning of
switching to group_vars which has additional information
as well.

Change-Id: Ia99a5a954cdd9c7159e272844a8a646884a2d9f4
diff --git a/playbooks/roles/configure-installer/tasks/main.yml b/playbooks/roles/configure-installer/tasks/main.yml
index e33b2a8..9dabf69 100644
--- a/playbooks/roles/configure-installer/tasks/main.yml
+++ b/playbooks/roles/configure-installer/tasks/main.yml
@@ -42,7 +42,7 @@
 # place generated kubespray inventory to kubespray/inventory/engine
 - name: Place inventory
   copy:
-    src: "{{ config_path }}/inventory.ini"
+    src: "{{ inventory_path }}/inventory.ini"
     dest: "{{ engine_cache }}/repos/kubespray/inventory/engine/inventory.ini"
     mode: 0644