Define the default sorting method per board

[Hercanic]

We can click on a column's title to sort a board by that column. This is only an end-user's customization, though. To make it useful to the admin for their users, how about the ability to define in the admin panel how a forum is sorted by default, beyond "Most Recent Post"? This would be of use to specialized boards that may need threads organized by subject, etc.

This is featured on Invision boards, while editing a forum.

Default sort key
- Date of last post
- Topic Title
- Topic Starter's Name
- Topic Posts
- Topic Views
- Date Topic Started
- Name of the Last Poster

Default sort order
- Descending (Z - A, 0 - 10)
- Ascending (A - Z, 10 - 0)