Allow us to mark dramas as favorites, and show number of favorites on the drama page

I think it would be cool if we could mark dramas (or movies) as favorites.

Each drama page would display the number of favorites, and each user page would display a list of that user's favorites.  "Most favorited" can also be a sorting option on the browse page.

The actor pages already have this feature, so I guess some of the code can be reused.