Set max size for external S3 upload requests

Fix uploads failing when exceeding the default nginx limit

site-cookbooks/kosmos_garage/templates/nginx_conf_s3.erb

@@ -16,6 +16,8 @@ server {
 
   error_page 401 403 404 500 /__empty-page.html;
 
+  client_max_body_size <%= @max_part_upload_size_mb %>m;
+
   location = /__empty-page.html {
     internal;
     return 200 "";