Optimize Network Manager to not need synchronization

Removes synchronization from sending packets
Makes normal packet sends no longer need to be wrapped and queued like it use to work.
Adds more packet queue immunities on top of keep alive to let the following scenarios go out
without delay:
  - Keep Alive
  - Chat
  - Kick
  - All of the packets during the Player Joined World event

Hoping that latter one helps join timeout issues more too for slow connections.

Removes processing packet queue off of main thread
  - for the few cases where it is allowed, order is not necessary nor
    should it even be happening concurrently in first place (handshaking/login/status)

Ensures packets sent asynchronously are dispatched on main thread

This helps ensure safety for ProtocolLib as packet listeners
are commonly accessing world state. This will allow you to schedule
a packet to be sent async, but itll be dispatched sync for packet
listeners to process.

This should solve some deadlock risks

This may provide a decent performance improvement because thread synchronization incurs a cache reset
so by avoiding ever entering a synchronized block, we get to avoid that, and packet sending is a really
hot activity.

Spigot-Server-Patches/Configurable-Keep-Spawn-Loaded-range-per-world.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Configurable Keep Spawn Loaded range per world
 This lets you disable it for some worlds and lower it for others.
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index 572679e4d1..071e5e7f72 100644
+index 572679e4d1c..071e5e7f729 100644
 --- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 @@ -0,0 +0,0 @@ public class PaperWorldConfig {
@@ -21,7 +21,7 @@ index 572679e4d1..071e5e7f72 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
-index 45882ee30f..0ee1d8e486 100644
+index 45882ee30f5..0ee1d8e4869 100644
 --- a/src/main/java/net/minecraft/server/MinecraftServer.java
 +++ b/src/main/java/net/minecraft/server/MinecraftServer.java
 @@ -0,0 +0,0 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
@@ -60,7 +60,7 @@ index 45882ee30f..0ee1d8e486 100644
          // CraftBukkit start
          // this.nextTick = SystemUtils.getMonotonicMillis() + 10L;
 diff --git a/src/main/java/net/minecraft/server/WorldLoadListener.java b/src/main/java/net/minecraft/server/WorldLoadListener.java
-index d6762d3853..7b6f5b2da0 100644
+index d6762d3853b..7b6f5b2da0a 100644
 --- a/src/main/java/net/minecraft/server/WorldLoadListener.java
 +++ b/src/main/java/net/minecraft/server/WorldLoadListener.java
 @@ -0,0 +0,0 @@ public interface WorldLoadListener {
@@ -71,7 +71,7 @@ index d6762d3853..7b6f5b2da0 100644
 +    void setChunkRadius(int radius); // Paper - allow changing chunk radius
  }
 diff --git a/src/main/java/net/minecraft/server/WorldLoadListenerLogger.java b/src/main/java/net/minecraft/server/WorldLoadListenerLogger.java
-index 3868572aed..ae77805f71 100644
+index 3868572aed5..ae77805f71c 100644
 --- a/src/main/java/net/minecraft/server/WorldLoadListenerLogger.java
 +++ b/src/main/java/net/minecraft/server/WorldLoadListenerLogger.java
 @@ -0,0 +0,0 @@ import org.apache.logging.log4j.Logger;
@@ -102,7 +102,7 @@ index 3868572aed..ae77805f71 100644
      @Override
      public void a(ChunkCoordIntPair chunkcoordintpair) {
 diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
-index 081df240f3..ce506e0e12 100644
+index 081df240f30..ce506e0e129 100644
 --- a/src/main/java/net/minecraft/server/WorldServer.java
 +++ b/src/main/java/net/minecraft/server/WorldServer.java
 @@ -0,0 +0,0 @@ public class WorldServer extends World {
@@ -199,7 +199,7 @@ index 081df240f3..ce506e0e12 100644
  
      public LongSet getForceLoadedChunks() {
 diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-index 5ea7b0b25a..8f8c18c5a4 100644
+index 5ea7b0b25ae..8f8c18c5a4f 100644
 --- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 +++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 @@ -0,0 +0,0 @@ public class CraftWorld implements World {