Backup/restore process needs to handle ids in the 'other' field

With the introduction of MDL-46455 the standard/database log stores will be able to backup/restore logs. Both these log stores store the 'other' information for events. Some of these events rely on the 'other' information to be accurate in order to display a description etc. We need to convert the information in this field when restoring the logs to store the correct ids.