fix: Adds AfterSerialize support. Removes BeforeSerialize support. (#1208)

### Changes
* Implements an AfterSerialize method that is executed synchronously.
* Removes `BeforeSerialize` support since it was dangerous in its current implementation.
* Moves PlayerMobile kill/virtual decay to AfterSerialize.
* Adds kill decay to after Deserialize.

Projects/UOContent/Accounting/Account.cs

@@ -295,10 +295,6 @@ namespace Server.Accounting
 
         public Serial Serial { get; set; }
 
-        public void BeforeSerialize()
-        {
-        }
-
         [AfterDeserialization]
         private void AfterDeserialization()
         {
@@ -337,6 +333,12 @@ namespace Server.Accounting
             }
         }
 
+        public bool ShouldExecuteAfterSerialize => false;
+
+        public void AfterSerialize()
+        {
+        }
+
         /// <summary>
         ///     Deletes the account, all characters of the account, and all houses of those characters
         /// </summary>