Add a log channel for rig control

RIGCTRL is defined as a log channel for rig control messages and the
appropriate logger is made available to children of the Transceiver
class. Use Transceiver::logger() to access the logger.

Switched existing rig control QDebug messages to Boost logging.

Transceiver/TransceiverBase.cpp

@@ -41,7 +41,7 @@ void TransceiverBase::start (unsigned sequence_number) noexcept
 void TransceiverBase::set (TransceiverState const& s,
                            unsigned sequence_number) noexcept
 {
-  TRACE_CAT ("TransceiverBase", "#:" << sequence_number << s);
+  TRACE_CAT ("#: " << sequence_number << " " << s);
 
   QString message;
   try