feat: add CEntityKeyValues with dispatch

[roflmuffin]

Example from the tests:

var light = Utilities.CreateEntityByName<CBarnLight>("light_barn")!;
using var kv = new CEntityKeyValues();

kv.SetColor("color", Color.BlanchedAlmond);
kv.SetFloat("brightness", 750.0f);
kv.SetBool("enabled", true);
kv.SetVector("size_params", new Vector(60.0f, 120.0f, 0.05f));
kv.SetInt("directlight", 3);
light.DispatchSpawn(kv);

Assert.Equal(750.0f, light.Brightness);
Assert.Equal(Color.BlanchedAlmond.ToArgb(), light.Color.ToArgb());
Assert.True(light.Enabled);
Assert.Equal(60.0f, light.SizeParams.X);
Assert.Equal(120.0f, light.SizeParams.Y);
Assert.Equal(0.05f, light.SizeParams.Z);
Assert.Equal(3, light.DirectLight);

light.Remove();

This will no doubt lead to more memory leaks if you are creating Vector3, Quaternion etc. to pass into key values; but this will be resolved in the v2 branch once I bring these changes forward (and everything becomes struct based).