CSS color module level 5 color space support

[Ogeon]

Description

CSS has a few variants of color spaces that aren't yet supported in Palette. These should be added.

XYZ:

• xyz, xyz-d65 - Xyz or explicitly Xyz<D65>
• xyz-d50 - Xyz<D50>

RGB:

• Hex color - Srgb::<u8>::from_str
• Named color - palette::named
• rgb() and rgba() - Srgb, Srgba
• srgb - Rgb, Srgb or explicitly Rgb<Srgb>
• srgb-linear - LinSrgb
• display-p3 - Separate issue: Display P3 (and DCI-P3) support #367, implemented in Add DCI-P3, DCI-P3+, and Display P3 #412
• a98-rgb - Implemented in Add Adobe RGB #411
• prophoto-rgb - Implemented in Add ProPhoto RGB standard #413
• rec2020 - Implemented in Add Rec. 709 and Rec. 2020 #410

Other:

• hsl() and hsla() - Hsl<Srgb>, Hsla<Srgb>
• hwb() - Hwb<Srgb>
• lab() - Lab<D50>
• lch() - Lch<D50>
• oklab() - Oklab
• oklch() - Oklch
• device-cmyk (naive or value container) - Separate issue: CMYK #6

https://www.w3.org/TR/css-color-5

Motivation

CSS is widely used and providing matching options makes it easier for applications to use Palette as the color management backend when reading and writing CSS color syntax.