mozangle backend support.

[WangHoi]

We need to support d3d9 or d3d11 backend, can be accomplished by supporting 'mozangle'(ANGLE) backend.
Because Nvidia opengl driver crash on resizing opengl window, reported many times on Godot game engine issues.

Our app just fallback to cpu raster when detected Nvidia cards on win10/win11, poor performance.

[syrel]

I have an example of skia + mozangle (d3d11) + winit.
@pragmatrix I also have an example of skia + d3d12 + winit. Would you prefer them as examples or [[bin]] targets? Since cargo does not support dependencies per example many crates tend to convert examples to [[bin]] to not pollute dev-dependencies. What do you think?
It could be useful to have examples of skia + winit with pretty much all backends.

[pragmatrix]

@syrel Either way is fine, the advantage of [[bin]] I guess would be that we could share the code that renders the rust-skia animation in the examples.

Regarding examples in general. I am a bit concerned because of the cost in terms of long term maintenance. While I do think we should maintain examples for all backends, I also must state that examples in this repository are hard to maintain because of their additional platform specific dependencies they introduce.

BTW: I've built a full winit + D3D12 backend built for rust-skia, primarily because I wasn't able to get the latency down with Vulkan or OpenGL on Windows, which I now regret not open sourcing it. This project is definitely too large to be included here. So I hope that future example applications are not supplying any more gorillas than needed.