FIX: ensure we can download maxmind without redis or db config

This also corrects FileHelper.download so it supports "follow_redirect"
correctly (it used to always follow 1 redirect) and adds a `validate_url`
param that will bypass all uri validation if set to false (default is true)

app/controllers/uploads_controller.rb

@@ -134,6 +134,7 @@ class UploadsController < ApplicationController
         maximum_upload_size = [SiteSetting.max_image_size_kb, SiteSetting.max_attachment_size_kb].max.kilobytes
         tempfile = FileHelper.download(
           url,
+          follow_redirect: true,
           max_file_size: maximum_upload_size,
           tmp_file_name: "discourse-upload-#{type}"
         ) rescue nil