Find an approach for the file paths in the gpu apps

We should think about a good solution for the paths in the gpu apps. E.g. in the app WTG_RUB there are multiple paths for different machines:

// std::string path("D:/out/WTG_RUB"); // Mollok
// std::string inputPath("D:/out/WTG_RUB/input/");

std::string path("/workspaces/VirtualFluids_dev/output/WTG_RUB_Results/"); // Aragorn
std::string inputPath("/workspaces/VirtualFluids_dev/stl/WTG_RUB/");

One solution would be to set these paths in the config file. But this approach might just move the problem to another location. Do you have any ideas?

@m.schoenherr @soe.peters