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/ItemPacketTests.cs

@@ -497,8 +497,8 @@ namespace Server.Tests.Network
         [Fact]
         public void TestContainerContent()
         {
-            var cont = new Container(Serial.LastItem + 1);
-            cont.AddItem(new Item(Serial.LastItem + 2));
+            var cont = new Container(World.NewItem);
+            cont.AddItem(new Item(World.NewItem));
 
             var m = new Mobile(0x1);
             m.DefaultMobileInit();
@@ -549,8 +549,8 @@ namespace Server.Tests.Network
         [Fact]
         public void TestContainerContent6017()
         {
-            var cont = new Container(Serial.LastItem + 1);
-            cont.AddItem(new Item(Serial.LastItem + 2));
+            var cont = new Container(World.NewItem);
+            cont.AddItem(new Item(World.NewItem));
 
             var m = new Mobile(0x1);
             m.DefaultMobileInit();