feat: Upgrades serialization v4 (Threaded Heap Serialization) (#1947)

### Summary

- `GenericEntityPersistence` is now a type of `GenericPersistence`. This allows developers to serialize both entities and non-entities in the same system. 🎉
- Each `SerializationThreadWorker` now allocates 1MB of heap for serialization _permanently_. If more memory is needed, that thread will double it's memory, not to exceed increments of 64MB.
- Several bugs with serialization introduced with the pure MMF implementation have been fixed.
- `BinaryFileReader` has been added back. 🎉
- Adds `world.useMultithreadedSaves` to allow disabling threaded saves.

> [!IMPORTANT]
> **Developer Note**
> The split file serialization has been deprecated and is no longer used. We have effectively gone back to the same file writing we had before the pure MMF implementation.

Projects/UOContent/Accounting/Account.cs

@@ -284,6 +284,10 @@ public partial class Account : IAccount, IComparable<Account>
 
     public Serial Serial { get; set; }
 
+    public byte SerializedThread { get; set; }
+    public int SerializedPosition { get; set; }
+    public int SerializedLength { get; set; }
+
     [AfterDeserialization(false)]
     private void AfterDeserialization()
     {

Projects/UOContent/Engines/Bulk Orders/Books/BaseBOBEntry.cs

@@ -26,6 +26,10 @@ public abstract partial class BaseBOBEntry : IBOBEntry
 
     public Serial Serial { get; }
 
+    public byte SerializedThread { get; set; }
+    public int SerializedPosition { get; set; }
+    public int SerializedLength { get; set; }
+
     public bool Deleted { get; private set; }
 
     public BaseBOBEntry()

Projects/UOContent/Engines/Ethics/Core/EthicsEntity.cs

@@ -16,6 +16,10 @@ public partial class EthicsEntity : ISerializable
 
     public Serial Serial { get; }
 
+    public byte SerializedThread { get; set; }
+    public int SerializedPosition { get; set; }
+    public int SerializedLength { get; set; }
+
     public bool Deleted { get; private set; }
 
     public void Delete()

Projects/UOContent/Gumps/AdminGump.cs

@@ -3968,7 +3968,14 @@ namespace Server.Gumps
                 InvokeCommand("Save");
             }
 
-            Core.Kill(restart);
+            // Kill the server on a different thread otherwise we will dead lock
+            ThreadPool.QueueUserWorkItem(
+                _ =>
+                {
+                    World.WaitForWriteCompletion();
+                    Core.Kill(restart);
+                }
+            );
         }
 
         private void InvokeCommand(string c)