Create helper class for creating subdomains on multiple GPUs

.gitlab-ci.yml

CMake/cmake_config_files/ARAGORN.config.cmake

CMake/cmake_config_files/ARAGORNUBUNTU.config.cmake

CMake/cmake_config_files/ELDARION.config.cmake

CMake/cmake_config_files/KI4ALLGPU.config.cmake

CMake/cmake_config_files/MULE.config.cmake

CMake/cmake_config_files/PHOENIX.config.cmake

apps/gpu/ChannelFlow/ChannelFlow.cpp

apps/gpu/DrivenCavityMultiGPU/DrivenCavityMultiGPU.cpp

apps/gpu/DrivenCavityMultiGPU/configDrivenCavityMultiGPU.txt

apps/gpu/DrivenCavityMultiGPU/configPhoenix1GPU.txt

apps/gpu/DrivenCavityMultiGPU/configPhoenix8GPU.txt

apps/gpu/DrivenCavityMultiGPU/drivencavity_1gpu.cfg

...DrivenCavityMultiGPU/drivencavity_regressiontest_4gpu.cfg

...DrivenCavityMultiGPU/drivencavity_regressiontest_8gpu.cfg

apps/gpu/MusselOyster/configMusselOyster.txt

apps/gpu/SphereMultiGPU/CMakeLists.txt

apps/gpu/SphereMultiGPU/SphereMultiGPU.cpp

apps/gpu/SphereMultiGPU/sphere_1gpu.cfg

apps/gpu/SphereMultiGPU/sphere_regressiontest_4gpu.cfg