Modernized build paths in CMakeLists.txt

CMakeLists.txt

src/Python/CMakeLists.txt

src/TNL/Experimental/Arithmetics/UnitTests/CMakeLists.txt

src/Tools/CMakeLists.txt

src/UnitTests/Algorithms/CMakeLists.txt

src/UnitTests/CMakeLists.txt

src/UnitTests/Communicators/CMakeLists.txt

src/UnitTests/Containers/CMakeLists.txt

src/UnitTests/Containers/Segments/CMakeLists.txt

src/UnitTests/Containers/ndarray/CMakeLists.txt

src/UnitTests/Functions/CMakeLists.txt

src/UnitTests/Matrices/CMakeLists.txt

src/UnitTests/Matrices/Legacy/CMakeLists.txt

src/UnitTests/Meshes/CMakeLists.txt

src/UnitTests/Meshes/DistributedMeshes/CMakeLists.txt

src/UnitTests/Pointers/CMakeLists.txt