Added Particle-Swarm Optimizer

[m4rs-mt]

This PR adds a massively parallel particle-swarm based optimizer using the optimization engine API from PR #1028. It also includes full integration tests using simple objective functions.

The following code snippet shows a sample use case:

    public readonly struct Objective : IOptimizationFunction<Float32x2, float, float>
    {
        public float Evaluate(LongIndex1D index, Index1D dimension, SingleVectorView<Float32x2> positionView)
        {
            float result = 0;
            for (Index1D i = 0; i < dimension; ++i)
            {
                var vec = positionView[i];
                var dist = vec - new Float32x2(5.0f, 5.0f);
                result += dist.X * dist.X + dist.Y * dist.Y;
            }
            return result / dimension;
        }

        public bool CurrentIsBetter(float current, float proposed) => current <= proposed;
    }

    static void Main()
    {
        using var context = Context.CreateDefault();
        using var accel = context.CreateCPUAccelerator(0, CPUAcceleratorMode.Parallel);
        var stream = accel.DefaultStream;

        var random = new Random();

        var lowerBounds = new float[] { 0.0f, 0.0f, 0.0f, 0.0f };
        var upperBounds = new float[] { 10.0f, 10.0f, 10.0f, 10.0f };

        using var pso = new PSO<Float32x2, float, float, XorShift128Plus>(accel, 512, 4);
        using var optimizer = pso.CreateOptimizer(stream, random, new Objective());

        pso.LoadBounds(stream, lowerBounds, upperBounds);
        pso.LoadParameters(stream, PSO.DefaultFloatParameters);

        var bestPosition = new float[] { 0.0f, 0.0f, 0.0f, 0.0f };

        var run = optimizer.BeginOptimization(stream, bestPosition, float.MaxValue);
        
        for (int i = 0; i < 128; ++i)
            run.Step();

        var result = run.FinishToCPUAsync();
    }

Note that this PR requires #1028 to be merged.

Co-authored by @dfki-mako
Co-authored by @dfki-jugr