As the cuda warnings are different on each platform and super badly documented, we switch to suppress all warnings for the GridGenerator.

Remove some compiler warnings and added some cuda warning suppressions for the GridGenerator, as they are cluttering the build output.

As all warnings from VirtualFluidsCPU might be removed, we added a new CI job wich only builds VirtualFluidsCPU and treats all warnings as errors.

Restructure the cmake cuda process. Remove the policy and always set CMAKE_CUDA_ARCHITECTURE to 30, if not set. This will fail when someone is trying to build with cuda 10.2 or higher, as cuda 10.2 minimum support is 52.

NOTICE: preferred way is to set CMAKE_CUDA_ARCHITECTURE as cmake argument OR in the config file to the real gpu architecture. For example phoenix tesla P100 have the compute capability 60.

Add gpu options to root cmake. Add the cmake option for passing the path to the numerial tests. Add git clone test to the CI.

Add a fix for the numerical tests, where all compile definitions were overwritten by set_target_properties().

Add gcov cmake and a python bindings cmake option (default off). Add the compiler flags also to the test targets.