This PR introduces `AnimationStyle`, it is used to override default animation curves and durations in several widgets.
fixes [Add the ability to customize MaterialApp theme animation duration](https://github.com/flutter/flutter/issues/78372)
fixes [Allow customization of showMenu transition animation curves and duration](https://github.com/flutter/flutter/issues/135638)
Here is an example where popup menu curve and transition duration is overriden:
```dart
popUpAnimationStyle: AnimationStyle(
curve: Easing.emphasizedAccelerate,
duration: Durations.medium4,
),
```
Set `AnimationStyle.noAnimation` to disable animation.
```dart
return MaterialApp(
themeAnimationStyle: AnimationStyle.noAnimation,
```
