Play few animations in sequence

**Is your feature request related to a problem? Please describe.**
My root problem is next: I need to have `RichText` option, since I need to show 3 words, typing, one after another, and all 3 words have different color.

**Describe alternatives you've considered**
As far as I can see - there is no option to use `RichText`. Here is why I was wondered if that is possible to use animation is sequence:
- first animation started and 2 other are stopped
- once first is done - second started
- once second is done - third started
But from my experiments it also didn't work well.

So is there any way to use animation in sequence?

Look at the existing animation widgets in the package, such as TypewriterAnimatedTextKit, to understand how animations are structured. The issue requires sequencing multiple animations, so examine the animation controllers and callbacks. Check if there are existing examples of chaining animations or if a new widget needs to be created. Test by modifying an existing animation to see how start/stop callbacks work.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.