DDS — Missing operations on DomainParticipantFactory and need for helper values

The resolution of issue 6816 added operation to get and set default QoS on all the entity factories except for the DomainParticipantFactory. This was an omission as this factory also needs to provide these operation such that DomainParticipant entities can also be created using default QoS.
The operation lookup_participant is defined in the PIM (section 2.1.2.2.2) and does not appear in the PSM
Furthermore, it would be desirable to have some utility constants in the IDL that can be used to indicate to the factory that default QoS should be used to construct an entity. This avoids having to explicitly get the default QoS in the case the application does not want to change any of the defaults. Helper constants can also be added for the specific case of constructing DataReader and DataWriter entities when the application wishes to indicate that the QoS should be obtaining by modifying the default values with the ones defined by the Topic Qos

see below