Display the task description instead of "Drag & drop me" when hovering tasks

[paraita]

The "Drag & drop me" message that appears when hovering tasks from the toolboxes don't really add value to the Studio, as adding such tasks is already intuitive enough through a drag and drop or a simple click:

Instead, it would be more useful to display (if the info is available) the description of the task so the user can have more relevant info when hovering tasks from that toolbox.

[fviale]

+1 and we probably need to make sure at the same time, all tasks are properly documented