Replace the Transitions in the ListView with custom animations

Add/displace etc transitions don't work when the items change size during the animation
(showing/hiding the show more/show less button) in that case they will
animate to a wrong position and stay there

the kind of animation should be unchanged and work the same

BUG: 427894
FIXED-IN: 5.27

## Test case
```
for i in {1..6}; do
    notify-send foo bar -h string:desktop-entry:firefox
    sleep 1
done

for i in {1..6}; do
    notify-send foo bar -h string:desktop-entry:org.kde.dolphin
    sleep 1
done
```

Open Notifications widget

Close it

Open it again

Click "Show x more" button for any group