add narrow passage yaml

experiments/environments/narrow_passage.yaml

 circle_obstacles: []
-rectangle_obstacles: [[[0,6], [10,10]], [[0,0], [10,4]]]
+rectangle_obstacles: [[[3,6], [7,10]], [[3,0], [7,4]]]
 x_range: [0, 10]
 y_range: [0, 10]
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