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/0416-Add-moon-phase-API.patch

@@ -0,0 +1,22 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: BillyGalbreath <Blake.Galbreath@GMail.com>
+Date: Sun, 23 Aug 2020 16:32:11 +0200
+Subject: [PATCH] Add moon phase API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java b/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java
+index a9d3dbabd40e731dbe7db6cb957ed6d5b9856580..bb9b4ff9f5c983ef6fe0b295bc868bc1125921d5 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java
+@@ -505,4 +505,11 @@ public abstract class CraftRegionAccessor implements RegionAccessor {
+ 
+         throw new IllegalArgumentException("Cannot spawn an entity for " + clazz.getName());
+     }
++
++    // Paper start
++    @Override
++    public io.papermc.paper.world.MoonPhase getMoonPhase() {
++        return io.papermc.paper.world.MoonPhase.getPhase(this.getHandle().dayTime() / 24000L);
++    }
++    // Paper end
+ }