DDSPSMC11_ — Use consistent way to refer to vendor specific Delegate

The current DDS-PSM-Cxx spec often refers to the vendor specific Delegate in the following way:

• A typedef refers Entity<T> to detail::Entity<T>, which is in a vendor specific file.
• In detail::Entity, another typedef then substitutes the vendor specific Delegate for the template parameter.

However, for some unknown reason this pattern is not followed for the DataWriter and QueryCondition classes.

I propose to apply the same pattern to those classes as well.