Add perforated example with square-shaped holes

Plot-Scripts/PerforatedBilayer_square_parameterDependence.py

experiment/perforated-bilayer_square/PolarPlotLocalEnergy.py

experiment/perforated-bilayer_square/perfBilayer_test.py

...riment/perforated-bilayer_square/perforated_wood_lower.py

...riment/perforated-bilayer_square/perforated_wood_upper.py