Rewrite chunk system (#8177)

Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.

patches/server/0012-Timings-v2.patch

@@ -1309,7 +1309,7 @@ index 93d02b5de0721e3c5903e80bbf8b3b56ec3ab45d..4e7db441f68019d6e5d3359605b76bc4
      }
      // CraftBukkit end
 diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
-index 521f485366c65527ac3289dd27d8f2e311706a10..5833cc3d5014dad82607afc4d643b6bed885be64 100644
+index 3710f544a491a837b973daedc2dfa51357b70b56..e7fcb402e3d4e0707a28505a9fb6642764034e23 100644
 --- a/src/main/java/net/minecraft/server/players/PlayerList.java
 +++ b/src/main/java/net/minecraft/server/players/PlayerList.java
 @@ -1,5 +1,6 @@
@@ -1319,7 +1319,7 @@ index 521f485366c65527ac3289dd27d8f2e311706a10..5833cc3d5014dad82607afc4d643b6be
  import com.google.common.collect.Lists;
  import com.google.common.collect.Maps;
  import com.google.common.collect.Sets;
-@@ -1018,10 +1019,11 @@ public abstract class PlayerList {
+@@ -1019,10 +1020,11 @@ public abstract class PlayerList {
      }
  
      public void saveAll() {
@@ -1588,10 +1588,10 @@ index dec38e58e30c84887e9d29436c0f76c70c0a627d..be08224c8107aab3e9a3645a20977dd1
      private static final CraftPersistentDataTypeRegistry DATA_TYPE_REGISTRY = new CraftPersistentDataTypeRegistry();
      public CraftPersistentDataContainer persistentDataContainer;
 diff --git a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
-index ab986a3d1dc2f605b5b84d2b62cd97007e3a2c22..58a245b2ca6e65d491694142ad04d38236b46434 100644
+index bcd0287d99eeba2b3534b4a298dc4b79b293ec58..b322d9b7bd9e107a9adf995b6c4db4ff0af05fc1 100644
 --- a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
 +++ b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
-@@ -681,6 +681,7 @@ public class LevelChunk extends ChunkAccess {
+@@ -680,6 +680,7 @@ public class LevelChunk extends ChunkAccess {
              server.getPluginManager().callEvent(new org.bukkit.event.world.ChunkLoadEvent(this.bukkitChunk, this.needsDecoration));
  
              if (this.needsDecoration) {
@@ -1599,7 +1599,7 @@ index ab986a3d1dc2f605b5b84d2b62cd97007e3a2c22..58a245b2ca6e65d491694142ad04d382
                  this.needsDecoration = false;
                  java.util.Random random = new java.util.Random();
                  random.setSeed(this.level.getSeed());
-@@ -700,6 +701,7 @@ public class LevelChunk extends ChunkAccess {
+@@ -699,6 +700,7 @@ public class LevelChunk extends ChunkAccess {
                      }
                  }
                  server.getPluginManager().callEvent(new org.bukkit.event.world.ChunkPopulateEvent(this.bukkitChunk));