BHE; Move the function body in "CreateFlowAndTemperatureControl.h" to the cpp file.

In the case of the CXA/CXC or 2U BHE, we also need to call the function named "createFlowAndTemperatureControl", and this will cause an error of multiple definition when compiling. Besides, we also need to enrich flow and temperature boundary conditions including the BHE coupled with heat pump.