4075 New admin banner system

https://code.google.com/p/otwarchive/issues/detail?id=4075

Moves the banner out of the settings table and into its own table and gives the banners a makeover, allowing us to have different styles for alerts, events, and general notices.
The verbose class is only used on forms with four or more fieldsets. Because we're removing the fieldset for the banner, this no longer has enough fieldsets to keep the class.