[EDGEPOD-226] Add installing strongswan to router role

Also fixed ansible-lint failures

Change-Id: I78fbab0a9e2f45ea4f5989c255f09b47ef01bdcc
diff --git a/aether-playbook/site.yml b/aether-playbook/site.yml
index 8edda32..6f3ab97 100644
--- a/aether-playbook/site.yml
+++ b/aether-playbook/site.yml
@@ -40,10 +40,11 @@
 # 1) Assign SGI and S1U gateway address
 # 2) Add routing to UE pool
 # 3) Add SNAT rule for UE pool
+# 4) Install and configure VPN server
 - hosts: router
   any_errors_fatal: "{{ any_errors_fatal | default(true) }}"
   roles:
-    - { role: router, when: router_setup_enabled }
+    - { role: router, when: router_enabled or vpn_enabled }
 
 # K8S node setup
 # 1) Time synch