Added test files of 3BHEs case with 2U type.

Update the Test files for 3-BHEs array coupled pipe network example.
Update the Test file in Process HeatTransportBHE.
Add the computed 10th result file for 3-BHEs benchmark.
Modified the Tests.cmake file for HeatTransportBHE.
The test of 3 BHE requires python support.
Add copyright license into python scripts for 3 BHE case.