Add DCI-P3, DCI-P3+, and Display P3

[Kirk-Fox]

This pull request implements the DCI-P3, DCI-P3+, and Display P3 color spaces and standards.

• Closes Display P3 (and DCI-P3) support #367, by implementing the DCI-P3 and Display P3.
• Completes display-p3 task of CSS color module level 5 color space support #408, by implementing Display P3.

[codspeed-hq]

CodSpeed Performance Report

Merging #412 will improve performances by 20.29%

_{Comparing Kirk-Fox:master (068eccc) with master (fab4412)}

Summary

⚡ 1 improvements
✅ 46 untouched benchmarks

Benchmarks breakdown

	Benchmark	master	Kirk-Fox:master	Change
⚡	multiply_3x3	345.8 ns	287.5 ns	+20.29%

[Ogeon]

Thank you! I wanted to respond earlier, but I didn't find a good moment to sit down and have a proper look during the week.

The only real uncertainty from my part is the white point. I try to name constants and algorithms in a way that makes the origin clear. Sure, it's name spaced in this case, but it can easily escape out of context.

[Ogeon]

Alright, cool, thanks a lot! Once again, I appreciate all the help