drag and drop in server list

[gyorokpeter]

It should clearly indicate where the server will end up if dropped.
It must be able to distinguish between dropping an item as the last element of an open folder vs as the next element outside the folder.
Take accessibility into consideration, e.g. what if the user wants to move a server from the bottom of a 100 server list to the top. E.g. don't require using the mouse wheel while also holding down the left button or waiting for ages as the server list scrolls one by one.