feat: Add find_edges method to Image class (#383)

Closes #288

### Summary of Changes

Add method find_edges to Image that returns a new image containing the
edges but leaves the original unchanged.

<!-- Please provide a summary of changes in this pull request, ensuring
all changes are explained. -->

---------

Co-authored-by: patrikguempel <128832338+patrikguempel@users.noreply.github.com>

src/safeds/data/image/containers/_image.py

@@ -409,3 +409,17 @@ def rotate_left(self) -> Image:
         image_copy = copy.deepcopy(self)
         image_copy._image = image_copy._image.rotate(90, expand=True)
         return image_copy
+
+    def find_edges(self) -> Image:
+        """
+        Return a grayscale image with the highlighted edges.
+
+        Returns
+        -------
+        result : Image
+            The image with edges found.
+        """
+        image_copy = copy.deepcopy(self)
+        image_copy = image_copy.convert_to_grayscale()
+        image_copy._image = image_copy._image.filter(ImageFilter.FIND_EDGES)
+        return image_copy

tests/safeds/data/image/containers/test_image.py

@@ -404,3 +404,19 @@ def test_should_return_clockwise_rotated_image(self, image: Image, expected: Ima
     def test_should_return_counter_clockwise_rotated_image(self, image: Image, expected: Image) -> None:
         image = image.rotate_left()
         assert image == expected
+
+
+class TestFindEdges:
+    @pytest.mark.parametrize(
+        ("image", "expected"),
+        [
+            (
+                Image.from_png_file(resolve_resource_path("image/boy.png")),
+                Image.from_png_file(resolve_resource_path("image/edgyBoy.png")),
+            ),
+        ],
+        ids=["find_edges"],
+    )
+    def test_should_return_edges_of_image(self, image: Image, expected: Image) -> None:
+        image = image.find_edges()
+        assert image == expected