Support native events

## Describe the Feature

**Native Events** instead of ~js events~:
`onValueChange`
`onSlidingStart`
`onSlidingComplete`

## Possible Implementations

Supporting **native events** will unlock the abilities of `Animated.event` enabling tracking the Slider's value and animating stuff accordingly.
This will enable customizing this view to a large extent easily and with high performance.

Avoiding breaking changes can be achieved with a flag from props or by checking `typeof props.onValueChange === 'object'`

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### Android JS Impl
Uses `Slider` for `value` and renders the rest on top.
Native events will enhance this extremely and make *dev experience* easier (less code needed for customization)


## Related Issues