Refactored pe and mesapd load balancing to avoid interdependency

apps/benchmarks/GranularGas/CMakeLists.txt

apps/benchmarks/GranularGas/MESA_PD_KernelLoadBalancing.cpp

apps/benchmarks/GranularGas/MESA_PD_LoadBalancing.cpp

apps/benchmarks/GranularGas/PE_LoadBalancing.cpp

src/blockforest/loadbalancing/CMakeLists.txt

...ckforest/loadbalancing/level_determination/CMakeLists.txt

...alancing/level_determination/MinMaxLevelDetermination.cpp

...dbalancing/level_determination/MinMaxLevelDetermination.h

...lockforest/loadbalancing/weight_assignment/CMakeLists.txt

.../loadbalancing/weight_assignment/MetisAssignmentFunctor.h

...loadbalancing/weight_assignment/WeightAssignmentFunctor.h

src/pe/amr/CMakeLists.txt

tests/mesa_pd/domain/DynamicRefinement.cpp

tests/pe/MinMaxRefinement.cpp

tests/pe/RefinementWithSpareProcesses.cpp