Make Horizon parameters: vhost_extra_params and customization_module configurable

Horizon parameters - horizon::vhost_extra_params and horizon::customization_module
are available but not configurable using horizon. This change exposes these parameters
and makes them configurable.

Depends-On: Id204b60b2676f49713fb6ce7eede6200221f7163
Change-Id: I4875585530c6d1d3b1134577ef2e097216c6c348
(cherry picked from commit b27cc34d8b)

puppet/services/horizon.yaml

@@ -43,6 +43,17 @@ parameters:
   MonitoringSubscriptionHorizon:
     default: 'overcloud-horizon'
     type: string
+  HorizonVhostExtraParams:
+    default:
+      add_listen: false
+      priority: 10
+      access_log_format: '%a %l %u %t \"%r\" %>s %b \"%%{}{Referer}i\" \"%%{}{User-Agent}i\"'
+    description: Extra parameters for Horizon vhost configuration
+    type: json
+  HorizonCustomizationModule:
+    default: ''
+    description: Horizon has a global overrides mechanism available to perform customizations
+    type: string
 
 outputs:
   role_data:
@@ -64,10 +75,7 @@ outputs:
               - 443
         horizon::cache_backend: django.core.cache.backends.memcached.MemcachedCache
         horizon::django_session_engine: 'django.contrib.sessions.backends.cache'
-        horizon::vhost_extra_params:
-          add_listen: false
-          priority: 10
-          access_log_format: '%a %l %u %t \"%r\" %>s %b \"%%{}{Referer}i\" \"%%{}{User-Agent}i\"'
+        horizon::vhost_extra_params: {get_param: HorizonVhostExtraParams}
         horizon::bind_address: {get_param: [ServiceNetMap, HorizonNetwork]}
         horizon::django_debug: {get_param: Debug}
         horizon::keystone_url: {get_param: [EndpointMap, KeystoneInternal, uri]}
@@ -79,5 +87,6 @@ outputs:
                 - {get_param: HorizonSecret}
                 - {get_param: [DefaultPasswords, horizon_secret]}
         memcached_ipv6: {get_param: MemcachedIPv6}
+        horizon::customization_module: {get_param: HorizonCustomizationModule}
       step_config: |
         include ::tripleo::profile::base::horizon