Scroll horizontally when dragging cards

[Lamgiaosu1805]

When the list of group cards is long, you need to scroll to see it and drag the card to that group, the horizontal scrolling doesn't work

[CntrlX]

#23 has solved this.

[Taco55]

Speed of scrolling is too fast with the current fix. Ideally, scrolling is disabled (or has a slower speed) when an item is positioned in the middle of the screen.