feat(codegen): Adds AfterDeserialization support (#615)

Added the ability to execute arbitrary code after deserialization.

Example, let's say you want to delete an item after you deserialize it:
```cs
        [AfterDeserialization]
        private void OnAfterDeserialization()
        {
            Delete();
        }
```

Generates this:
```cs
        public override void Deserialize(IGenericReader reader)
        {
            base.Deserialize(reader);

            var version = reader.ReadEncodedInt();

            Timer.DelayCall(OnAfterDeserialization);
        }
```

Projects/SerializationGenerator/SerializableEntityGeneration/SerializableEntityGeneration.Class.cs

@@ -236,6 +236,7 @@ namespace SerializationGenerator
             // Deserialize Method
             source.GenerateDeserializeMethod(
                 compilation,
+                classSymbol,
                 isOverride,
                 version,
                 encodedVersion,