Un-hardcoding horizon server address

The patch makes a possible to change horizon address
which could be used  by horizon by soft param.

Change-Id: Ib4794406612fdb61377ac341314268494b07ee66
Related-PROD: PROD-25528
diff --git a/horizon/server/single.yml b/horizon/server/single.yml
index e1ceb2d..73fbcc3 100644
--- a/horizon/server/single.yml
+++ b/horizon/server/single.yml
@@ -11,7 +11,7 @@
     server:
       branding: ${_param:horizon_site_branding}
       bind:
-        address: 0.0.0.0
+        address: ${_param:horizon_server_bind_address}
         port: 8078
       plugin: {}
       session: