C bindings for Skia

These have been tailored to the needs of my specific projects and my not be suitable for anyone else.

Skia version

The Skia version with which these bindings have been tested is from Wed Nov 10 21:38:56 2021 +0000

• https://skia.googlesource.com/skia/+/6fae0523629f9abf114d8b7413f71dc7295a13e0
• https://chromium.googlesource.com/chromium/tools/depot_tools.git/+/4d3319e39c9b50747f47da35a351d428a38bcc82

Noticable changes in Skia code base reflected here

November 10, 2021

• SkFilterQuality is gone. https://skia.googlesource.com/skia/+/aebe248575affab2137f3d3fb9f94b8e397c4986