Allow enabling sand duping (#10191)

Because this exploit has been widely known for years and has not been fixed by Mojang, we decided that it was worth allowing people to toggle it on/off due to how easy it is to make it configurable.

It should be noted that this decision does not promise all future exploits will be configurable.

patches/server/0385-Improve-Arrow-API.patch

@@ -0,0 +1,38 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Nesaak <52047222+Nesaak@users.noreply.github.com>
+Date: Sat, 23 May 2020 10:31:11 -0400
+Subject: [PATCH] Improve Arrow API
+
+Add method to get the arrow's itemstack and a method
+to set the arrow's "noclip" status
+
+Co-authored-by: Jake Potrebic <jake.m.potrebic@gmail.com>
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftArrow.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftArrow.java
+index 35d8fbd9c5751568a1a3b8928017e23cd41bb163..762c395e45a681a11f3fe9d10e7f0ba310786e80 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftArrow.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftArrow.java
+@@ -99,6 +99,23 @@ public class CraftArrow extends AbstractProjectile implements AbstractArrow {
+         this.getHandle().pickup = net.minecraft.world.entity.projectile.AbstractArrow.Pickup.byOrdinal(status.ordinal());
+     }
+ 
++    // Paper start
++    @Override
++    public org.bukkit.craftbukkit.inventory.CraftItemStack getItemStack() {
++        return org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(getHandle().getPickupItem());
++    }
++
++    @Override
++    public void setNoPhysics(boolean noPhysics) {
++        this.getHandle().setNoPhysics(noPhysics);
++    }
++
++    @Override
++    public boolean hasNoPhysics() {
++        return this.getHandle().isNoPhysics();
++    }
++    // Paper end
++
+     @Override
+     public void setTicksLived(int value) {
+         super.setTicksLived(value);