Add Arrangement.BottomReversed to reverse column direction

ui/src/main/java/de/mm20/launcher2/ui/layout/Arrangement.kt

@@ -0,0 +1,40 @@
+package de.mm20.launcher2.ui.layout
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.runtime.Stable
+import androidx.compose.ui.unit.Density
+
+@Stable
+val Arrangement.BottomReversed: Arrangement.Vertical
+    get() = object : Arrangement.Vertical {
+        override fun Density.arrange(
+            totalSize: Int,
+            sizes: IntArray,
+            outPositions: IntArray
+        ) = placeRightOrBottom(totalSize, sizes, outPositions, reverseInput = true)
+
+        override fun toString() = "Arrangement#BottomReversed"
+    }
+
+internal fun placeRightOrBottom(
+    totalSize: Int,
+    size: IntArray,
+    outPosition: IntArray,
+    reverseInput: Boolean
+) {
+    val consumedSize = size.fold(0) { a, b -> a + b }
+    var current = totalSize - consumedSize
+    size.forEachIndexed(reverseInput) { index, it ->
+        outPosition[index] = current
+        current += it
+    }
+}
+private inline fun IntArray.forEachIndexed(reversed: Boolean, action: (Int, Int) -> Unit) {
+    if (!reversed) {
+        forEachIndexed(action)
+    } else {
+        for (i in (size - 1) downTo 0) {
+            action(i, get(i))
+        }
+    }
+}