Updated Upstream (Bukkit/CraftBukkit), deprecate SentientNPC API

Upstream has added the equivalent of our SentientNPC API, with exception to the EnderDragon.

We've added Mob to the EnderDragon, and our SentientNPC API should behave the same.

Vex#getOwner has been deprecated and a replacement Vex#getSummoner has been added using Mob.

However, since 1.13 is not production ready, SentientNPC API is subject for removal in 1.13.1 since
1.13 API is not compatible with 1.12.

Please move to the Mob interface ASAP.

This update has not been tested by PaperMC and as with ANY update, please do your own testing

Bukkit Changes:
c5ab54d8 Expand GameRule API
ab9a606c Improve entity hierarchy by adding Mob interface.

CraftBukkit Changes:
29e75648 Expand GameRule API
50e6858b Improve entity hierarchy by adding Mob interface.
0e1d79b4 Correct error in previous patch

Spigot-Server-Patches/0302-Add-async-chunk-load-API.patch

@@ -1,41 +0,0 @@
-From 35783dd499e0ca36931e371b18f56a03414bb1e0 Mon Sep 17 00:00:00 2001
-From: Aikar <aikar@aikar.co>
-Date: Sat, 21 Jul 2018 16:55:04 -0400
-Subject: [PATCH] Add async chunk load API
-
-
-diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-index 54a605f9b9..f4dc7e4ac6 100644
---- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-@@ -156,6 +156,27 @@ public class CraftWorld implements World {
-         }
-     }
- 
-+    // Paper start - Async chunk load API
-+    public void getChunkAtAsync(final int x, final int z, final ChunkLoadCallback callback) {
-+        final ChunkProviderServer cps = this.world.getChunkProviderServer();
-+        callback.onLoad(cps.getChunkAt(x, z).bukkitChunk); // TODO: Add back async variant
-+        /*cps.getChunkAt(x, z, new Runnable() {
-+            @Override
-+            public void run() {
-+                callback.onLoad(cps.getChunkAt(x, z).bukkitChunk);
-+            }
-+        });*/
-+    }
-+
-+    public void getChunkAtAsync(Block block, ChunkLoadCallback callback) {
-+        getChunkAtAsync(block.getX() >> 4, block.getZ() >> 4, callback);
-+    }
-+
-+    public void getChunkAtAsync(Location location, ChunkLoadCallback callback) {
-+        getChunkAtAsync(location.getBlockX() >> 4, location.getBlockZ() >> 4, callback);
-+    }
-+    // Paper end
-+
-     public Chunk getChunkAt(int x, int z) {
-         return this.world.getChunkProviderServer().getChunkAt(x, z).bukkitChunk;
-     }
--- 
-2.18.0
-