Updates Serialization (#292)

- [X] Removes all save strategies
- [X] Removes duplicate file writer that won't be used
- [X] Removes persistence (it will become a duplicate system)
- [X] Add a save position variable to skip serializing a clean item/mobile
- [X] Update Guilds/Accounts to be IEntity types
    - Because guilds are abstract, this may make serialization tricky.
- [X] Update the generalized IEntity writing
- [X] Update the load/save to write to buffers then to files in background


Bumps release version

Projects/Server.Tests/Network/Packets/Old/Outgoing/MenuPacketTests.cs

@@ -145,7 +145,7 @@ namespace Server.Tests.Network
             var m = new Mobile(0x1);
             m.DefaultMobileInit();
 
-            var item = new ContextMenuItem(Serial.LastItem + 1);
+            var item = new ContextMenuItem(World.NewItem);
             var menu = new ContextMenu(m, item);
 
             var data = new DisplayContextMenu(menu).Compile();
@@ -196,7 +196,7 @@ namespace Server.Tests.Network
             var m = new Mobile(0x1);
             m.DefaultMobileInit();
 
-            var item = new ContextMenuItem(Serial.LastItem + 1);
+            var item = new ContextMenuItem(World.NewItem);
             var menu = new ContextMenu(m, item);
 
             var data = new DisplayContextMenuOld(menu).Compile();