Support Rtl in SplitPane

[ahmedhosnypro]

This is related to issue: #4258

changes

• DesktopSplitPane.kt: placable.place() -> placable.placeRelative

• SplitePaneDSL.kt: change the delta direction to follow the layout direction

 @Composable
    override fun Modifier.markAsHandle(): Modifier = this.run {
        val layoutDirection = LocalLayoutDirection.current
        pointerInput(containerScope.splitPaneState) {
            detectDragGestures { change, _ ->
                change.consume()
                containerScope.splitPaneState.dispatchRawMovement(
                    if (containerScope.isHorizontal)
                        if (layoutDirection == LayoutDirection.Ltr) change.position.x else -change.position.x
                    else change.position.y
                )
            }
        }

the problem with .onPointerEvent() Modifier, or onDrag also, is
whenever the layout direction is Ltr or Rtl:
moving to right always produce positive change, [expected negative if dir =Rtl]
moving to left always produce negative change, [expected positive if dir =Rtl]

the calculation of postion will fail if layoutDir is Rtl, because positionPercentage will be out of range

fun dispatchRawMovement(delta: Float) {
        val movableArea = maxPosition - minPosition
        if (movableArea > 0) {
            positionPercentage =
                ((movableArea * positionPercentage) + delta).coerceIn(0f, movableArea) / movableArea
        }
    }

[igordmn]

Thanks!