Move collision kernel to lbm module

Description started in VirtualFluids Paper section 7.2

lbm

new folder in lbm: collision contains:

• K17CompressibleNavierStokes::runK17CompressibleNavierStokes()

• struct CollisionParameter

• TurbulenceModel moved from VirtualFluids_GPU

• removes some old unused function and classes from lbm module (BGK and CumulantChimera was old attempt of having collision kernel in lbm module)

gpu

• small refactorings:
  • removed old DistributionHelper class (was redundant to LBM/GPUHelperFunctions/KernelUtilities)
  • removed old "unified" kernel

important changes happend in:

• K17CompressibleNavierStokes
  • is creating GPUCollisionParameter and calling the global runCollision function
  • Declares the actual collision kernel function and passes it to the runCollision
• RunLBMCollision
  • does gpu specific things
  • creates the hardware independent structure CollisionParameter from GPUCollisionParameter and calls the actual collision kernel, which was passed as an argument

cpu

• new kernel class K17CompressibleNavierStokesmakes use of new lbm module (fits the new naming schema)
• FlowAroundCylinder was based on old CompressibleCumulantLBMKernel. Its now using the K17CompressibleNavierStokes.

TODO:

• update reference data for all regression tests
• do squash commit