models: stop saving IP addresses in version tables.

Mark various `creator_ip_addr` and `updater_ip_addr` columns as ignored
and stop updating them in preparation for dropping them.

app/models/upload.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Upload < ApplicationRecord
+  self.ignored_columns = [:uploader_ip_addr]
+
   extend Memoist
   class Error < StandardError; end