DDS15 — ContentFilteredTopics should be removed. Filtering belongs to DataReaders

The DDS v2.1 introduces the concept of a ContentFilteredTopic in order to express filtering on a DataReder. The ContentFilteredTopic is a local entity that is not distributed via discovery. In addition content filters are already distributed as part of DataReader discovery.

As such it would be cleaner and more sensible to remove the ContentFilteredTopic and allow to express the filter directly through either DataReader QoS or as a Filter parameter (see DDS-PSM-Cxx for inspiration).