Upload videos and correct links

Two of the test cases point to videos to show what a successful run looks
like. These were randomly stored on the old wiki machine. Rather than
having unlinked static content on the website, add these to the
`images` folder and update links.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>

test-cases/webkit2gtk-ac-animations.yaml

@@ -20,12 +20,12 @@ metadata:
     - "In the first URI, the two squares will rotate for 10 seconds. While
        rotating, they should have a blue border, which indicates they are AC
        layers. The expected rendering can be seen in the following video:"
-    -  "~https://www.apertis.org/static/AC-animation.ogv"
+    -  "~images/AC-animation.ogv"
     - "The second URI will again show two blue squares. Both will move to the
        right and animate their opacity at the same time, so will go from blue to
        white and back. They should have borders while animating. The expected
        rendering can be seen in the following video:"
-    - "~https://www.apertis.org/static/AC-animation-keyframe-opacity.ogv"
+    - "~images/AC-animation-keyframe-opacity.ogv"
     - "If the result does not match the squares as seen in the videos above, the
        test has failed."
 

test-cases/webkit2gtk-ac-scrolling.yaml

@@ -21,7 +21,7 @@ metadata:
     - "After the test page is loaded, the border of the GraphicsLayerActor must
        scroll in sync with the rest of the content as shown in the following
        video:"
-    - "~https://www.apertis.org/static/AC-scrolling.ogv"
+    - "~images/AC-scrolling.ogv"
     - "This test will be considered a PASS if it works with at least one of mouse
        or touchpad because this is not a test for the mouse or touchpad working."