LibGfx+LibWeb: Do some color management on images with an ICC profile

This patch introduces the `Gfx::ColorSpace` class, this is basically a
serializable wrapper for skia's SkColorSpace. Creation of the instances
of this class (and thus ICC profiles parsing) is performed in the
ImageDecoder process. Then the object is serialized and sent through
IPC, to finally be handed to skia for rendering.

However, to make sure that we're not making all LibGfx's users dependent
on Skia as well, we need to ensure the `Gfx::ColorSpace` object has no
dependency on objects from Skia. To that end, the only member of the
`ColorSpace` class is the opaque `ColorSpaceImpl` struct. Though, there
is on issue with that design, the code in `DisplayListPlayer.cpp` needs
access to the underlying `sk_sp<SkColorSpace>`. It is provided by a
template function, that is only specialized for this type.

Doing this work allows us to pass the following WPT tests:
- https://wpt.live/css/css-color/tagged-images-001.html
- https://wpt.live/css/css-color/tagged-images-003.html
- https://wpt.live/css/css-color/tagged-images-004.html
- https://wpt.live/css/css-color/untagged-images-001.html

Other test cases can also be found here:
- https://github.com/svgeesus/PNG-ICC-tests

Note that SkColorSpace support quite a limited amount of color spaces,
so color profiles like the ones in [1] or the v4 profiles in [2] are not
supported yet. In fact, SkColorSpace only accepts skcms_ICCProfile with
a linear conversion to XYZ D50.

[1] https://www.color.org/browsertest.xalter
[2] https://www.color.org/version4html.xalter

Libraries/LibWebView/Plugins/ImageCodecPlugin.cpp

@@ -54,6 +54,7 @@ NonnullRefPtr<Core::Promise<Web::Platform::DecodedImage>> ImageCodecPlugin::deco
             for (auto& frame : result.frames) {
                 decoded_image.frames.empend(move(frame.bitmap), frame.duration);
             }
+            decoded_image.color_space = move(result.color_space);
             promise->resolve(move(decoded_image));
             return {};
         },