Implement hack ordering

[andrewsosa]

On the judging page, judges should be able to easily rearrange hacks into the ordering of preference.

There should be a visual indicator that clearly displays which rank is which in addition to the way they are ordered.

• We may need to get a design for this

[andrewsosa]

This has been changed from the original intent.

The final judging tab should be a list of drop-down menus ordered in preference. Selecting a hack in another dropdown should unselect it in the other dropdown.