Cleaned up UniformGridGPU benchmark and adapted it to changes in python codegen packages

apps/benchmarks/UniformGridGPU/UniformGridGPU.cpp

apps/benchmarks/UniformGridGPU/UniformGridGPU.py

apps/benchmarks/UniformGridGPU/UniformGridGPU_AA.cpp

apps/benchmarks/UniformGridGPU/UniformGridGPU_AA.py

apps/benchmarks/UniformGridGPU/simulation_setup/base.py

apps/benchmarks/UniformGridGPU/simulation_setup/benchmark.py

...arks/UniformGridGPU/simulation_setup/benchmark_configs.py

.../benchmarks/UniformGridGPU/simulation_setup/inter_node.py

.../benchmarks/UniformGridGPU/simulation_setup/intra_node.py

...arks/UniformGridGPU/simulation_setup/pizdaint_jobfiles.py

...enchmarks/UniformGridGPU/simulation_setup/single_node.prm

...benchmarks/UniformGridGPU/simulation_setup/single_node.py

...chmarks/UniformGridGPU/simulation_setup/strong_scaling.py

...enchmarks/UniformGridGPU/simulation_setup/weak_scaling.py