Current Chunk for Entity and Block Entities, counts by entity type

This enables us a fast reference to the entities current chunk instead
of having to look it up by hashmap lookups.

We also store counts by type to further enable other performance optimizations in later patches.

Spigot-Server-Patches/Properly-remove-entities-on-dimension-teleport.patch

@@ -22,10 +22,10 @@ requirement, but plugins (such as my own) use this method to
 trigger a "reload" of the entity on the client.
 
 diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
-index 58fe1aa3e..4431f6e99 100644
+index 00791faf2..70641d479 100644
 --- a/src/main/java/net/minecraft/server/Entity.java
 +++ b/src/main/java/net/minecraft/server/Entity.java
-@@ -0,0 +0,0 @@ public abstract class Entity implements ICommandListener {
+@@ -0,0 +0,0 @@ public abstract class Entity implements ICommandListener, KeyedObject { // Paper
              }
              // CraftBukkit end */