transformations

changed the selection of Kernels - now we use the variables from KernelType.h in the parameter class an some apps

- renamed the mpi module to parallel
- removed the communicationRoutine interface from gpu. gpu now also uses the communicator interface from parallel
- added missing functionality in parallel/Communicator
- moved ws2_32 library dependency on windows from VirtualFluids_GPU to parallel

Remove old apps. Remove unused extensions. Add format checker extensions and flylint settings to workspace. Add multigpu build to all-apps.