[Design] HonkPerf.NET.GenericSIMD

[WhiteBlackGoose]

GenericSIMD

We're probably going to use Silk.NET.Maths for Simd128 and Simd256 sets. The API itself though would rely on Span<T>.

Current thought:

static void Add<T>(Span<T> a, Span<T> b, Span<T> c)