[WIP] start 1.15 port

reorganize packages to match Fabric version
use util classes from Fabric version

src/main/kotlin/mods/betterfoliage/util/Random.kt

@@ -0,0 +1,18 @@
+package mods.betterfoliage.util
+
+import net.minecraft.util.math.BlockPos
+import java.util.Random
+
+val random = Random(System.nanoTime())
+
+fun randomB() = random.nextBoolean()
+fun randomI(min: Int = 0, max: Int = Int.MAX_VALUE) = min + random.nextInt(max - min)
+fun randomD(min: Double = 0.0, max: Double = 1.0) = random.nextDouble() * (max - min) + min
+
+fun semiRandom(x: Int, y: Int, z: Int, seed: Int): Int {
+    var value = (x * x + y * y + z * z + x * y + y * z + z * x + (seed * seed))
+    value = (3 * x * value + 5 * y * value + 7 * z * value + (11 * seed))
+    return value shr 4
+}
+
+fun BlockPos.semiRandom(seed: Int) = semiRandom(x, y, z, seed)