Summary:
In addition to porting to TimeLine, this change also fixes quadratic
scaling of animation durations:

```lang=cpp
animData.fadeInDuration = animationTime(mFadeInTime);
animData.fadeOutDuration = animationTime(mFadeOutTime);
```

where

```lang=cpp
mFadeInTime = animationTime(...);
mFadeOutTime = animationTime(...);
```

Depends on D13740

Test Plan: Opened/closed Kickoff.

Reviewers: #kwin, mart

Reviewed By: #kwin, mart

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D13801