iOS native scroll and feel

[elijah-semyonov]

Proposed Changes

Implement CupertinoScrollDecayAnimationSpec to simulate iOS inertia equation.
Implement CupertinoOverscrollEffect to simulate rubber banding and spring effect.

Testing

Test: launch iOS app and test interaction between fling and overscroll

Notes

Comments for CupertinoOverscrollEffect.direction mention this behavior for 2D cases:
Left picture shows visual path of combined scroll offset (scrollable content offset + overscroll offset), rect represents bounds of values max(0, content.size - frame.size) for each dimension.
Right pictures show value over time (t) for X and Y components. Green changes are happening inside spring animation, blue inside fling animation. (t) scale is matching for both (bottom and top on the right).

Currently the API forces us to communicate with outer entities using velocities deltas, which is built on assumption that all these animations' stages happen in sync for both dimensions (which is not the case).

override suspend fun applyToFling(
        velocity: Velocity,
        performFling: suspend (Velocity) -> Velocity
    ) {
        val availableFlingVelocity = playInitialSpringAnimationIfNeeded(velocity)

        val velocityConsumedByFling = performFling(availableFlingVelocity)
        val postFlingVelocity = availableFlingVelocity - velocityConsumedByFling

        playSpringAnimation(
            lastFlingUncosumedDelta.toFloat(),
            postFlingVelocity.toFloat(),
            false
        )
    }