If a topic is moved it doesn't retain all of its info in the new forum, and if a topic is copied the copied posts don't retain any additional column info either. These events allow the modification of the sql queries that add this data to the database.
When I move an anonymous topic to a new forum, the columns that I've added to the topic to retain some anon information is not copied and people are outed. The same for copying a topic – the posts don't have any anon information in them. This PR solves these problems by adding a few core events so I can put additional info into the update/insert sql queries that these actions use without requiring any additional server or database load.