Import MAL lists for Manga

This uses the same upload box and should probably get some new copy in various places around the site to make this clear.  All it does is check if there's a `<manga>` node.

I'll probably stop using side-effects for setting `@list` later.  It requires the XML in hash form, so I have to do a minor little rearranging of the guts of the class to make that work, and right now I'm waaaaaaay too tired for that.

Also I ripped out MALDataImport because it's not used anywhere (that was the one for taking JSON and importing it for manga)

Oh, also, the `notes` column should probably be added to the serializer and displayed in the ember view like it is in Anime