integration: Use vars_files in plays

It's unsightly and hard to maintain collections of references and long
lists across multiple playbooks/include files.  Centralize them all
in ``vars.yml``, then include that in all plays.

Minor: Update all files with a newline at the start and end.

Signed-off-by: Chris Evich <cevich@redhat.com>

contrib/test/integration/main.yml

@@ -1,7 +1,7 @@
 - hosts: all
   remote_user: root
-  vars:
-    xunit: false
+  vars_files:
+    - "{{ playbook_dir }}/vars.yml"
   tags:
     - setup
   tasks:
@@ -28,8 +28,8 @@
 
 - hosts: all
   remote_user: root
-  vars:
-    xunit: false
+  vars_files:
+    - "{{ playbook_dir }}/vars.yml"
   tags:
     - integration
     - e2e
@@ -39,8 +39,8 @@
 
 - hosts: all
   remote_user: root
-  vars:
-    xunit: false
+  vars_files:
+    - "{{ playbook_dir }}/vars.yml"
   tags:
     - integration
   tasks:
@@ -49,8 +49,10 @@
 
 - hosts: all
   remote_user: root
+  vars_files:
+    - "{{ playbook_dir }}/vars.yml"
   tags:
     - e2e
   tasks:
     - name: run k8s e2e tests
-      include: e2e.yml
+      include: e2e.yml