ISPN-4528 Genericize remaining M/R internal classes

Master only. See https://issues.jboss.org/browse/ISPN-4528 for more details. 
These raw types warnings can be removed by just changing the declaration to be 

```
public static class DeltaListExternalizer extends AbstractExternalizer<DeltaList<E>>
```

and update the other methods I would think.