[PL] Move the similar parts between CXA and CXC to a basic class.

ProcessLib/HeatTransportBHE/BHE/BHECommonCoaxial.h

ProcessLib/HeatTransportBHE/BHE/BHE_CXA.cpp

ProcessLib/HeatTransportBHE/BHE/BHE_CXA.h

ProcessLib/HeatTransportBHE/BHE/BHE_CXC.cpp

ProcessLib/HeatTransportBHE/BHE/BHE_CXC.h

ProcessLib/HeatTransportBHE/BHE/BoreholeGeometry.cpp

ProcessLib/HeatTransportBHE/BHE/BoreholeGeometry.h

ProcessLib/HeatTransportBHE/BHE/CreateBHE1U.cpp

ProcessLib/HeatTransportBHE/BHE/CreateBHECXA.cpp

ProcessLib/HeatTransportBHE/BHE/CreateBHECXC.cpp

ProcessLib/HeatTransportBHE/BHE/GroutParameters.cpp

ProcessLib/HeatTransportBHE/BHE/GroutParameters.h

ProcessLib/HeatTransportBHE/BHE/Physics.h

ProcessLib/HeatTransportBHE/BHE/PipeConfigurationCoaxial.h

ProcessLib/HeatTransportBHE/BHE/RefrigerantProperties.cpp

ProcessLib/HeatTransportBHE/BHE/RefrigerantProperties.h

...Lib/HeatTransportBHE/BHE/ThermoMechanicalFlowProperties.h