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/Server/Items/Item.cs

@@ -802,6 +802,10 @@ public class Item : IHued, IComparable<Item>, ISpawnable, IObjectPropertyListEnt
     [CommandProperty(AccessLevel.Counselor)]
     public Serial Serial { get; }
 
+    public byte SerializedThread { get; set; }
+    public int SerializedPosition { get; set; }
+    public int SerializedLength { get; set; }
+
     public virtual void Serialize(IGenericWriter writer)
     {
         writer.Write(9); // version