Implement Material carousel sample

[zsoltk]

Based on specs: https://m3.material.io/components/carousel/overview

The simplest solution is possibly a SpotlightModel + a new MotionController derived from SpotlightSlider that has a sliding window mechanism:

• windowSize = 3 or 4 based on design specs, but should be a constructor arg
• left, right indices are maintained to be windowSize apart
• left, right indices are maintained to be pushed around by scrollX – i.e. if the scrollX value would go beyond the values stored in left or right, both of them move in that direction, maintaining their distance = this way the window can be "pushed around" automatically, but the active element can move around within the window bounds
• ui element target picking is done in 2 phases:
• 1st phase: windowSize elements are picked from the overall list, with the condition that their index is within left, right
• 2nd phase: each element in the window is compared against activeIndex to pick the right TargetUiState (small, medium, large)
• all other elements transition towards a TargetUiState hidden