add gzip compression to nginx host.conf

templates/nginx_site_config.j2

@@ -38,6 +38,10 @@ server {
     index index.html index.htm;
     error_page 404 /static/404.html;
 
+    gzip on;
+    gzip_types text/plain text/css application/javascript application/json;
+    gzip_vary on;
+
     location = /config.js {
         alias /etc/jitsi/meet/{{ jitsi_meet_server_name }}-config.js;
     }