refactor: change from standar backend api to python library

test-lib.py

@@ -0,0 +1,22 @@
+from math_problems_structure.grade_1 import join_pictures_with_quantity
+
+
+def main() -> None:
+    problem = join_pictures_with_quantity(
+        container_count_per_side=2,
+        available_pictures=[
+            {
+                "id": f"picture-{index}",
+                "name": f"Picture {index}",
+                "image_path": f"/images/{index}.png",
+            }
+            for index in range(4)
+        ],
+        seed=1,
+    )
+
+    print(problem)
+
+
+if __name__ == "__main__":
+    main()