Merge drop icons with direction icons for adding a component in place in a container

The current icons require 2x48px of space, this could easily become a problem with components as we can not control the height of customer components and the droparea might 'leak' out and functionality might break. We can improve the situation by merging both the direction and add icons into 1 which allows for 2x24px of space which is very doable and only 8px more then the previous minimum height.