[SOGo] Update SOGo to 5.5.1

**Includes Database Changes!**

As a preparation for 5.5.2 the database as well as some NGINX Settings have been changed.

data/conf/nginx/includes/site-defaults.conf

@@ -22,6 +22,10 @@
   add_header X-Permitted-Cross-Domain-Policies none;
   add_header Referrer-Policy strict-origin;
 
+  proxy_buffer_size 128k;
+  proxy_buffers 64 512k;
+  proxy_busy_buffers_size 512k;
+
   index index.php index.html;
 
   client_max_body_size 0;
@@ -163,7 +167,7 @@
     proxy_connect_timeout 75;
     proxy_send_timeout 3600;
     proxy_read_timeout 3600;
-    proxy_buffers 64 256k;
+    #proxy_buffers 64 256k;
     proxy_set_header X-Real-IP $remote_addr;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     proxy_set_header Host $http_host;