New less intensive custom scaler

[FineLine0]

Expected behavior 预期的功能

to be less intensive than NIS and FSR (magpie app), but better than Bilinear and Bicubic scalers.

This will help for people with 1440p/4K monitor who wants to play at 1080p without unnecessary blur of bilinear scaling.

Alternative behavior (optional) 近似的功能（可选）

No response

[Blinue]

FSR is very fast and you can adjust its sharpness in Magpie. It's good enough for 3D games, is there anything to improve?

[FineLine0]

maybe add NIS with a somewhat less intensive sharpening effect, as the sharpening from control panel takes away 6% of the performance which is crazy!

[Blinue]

I will add NIS and NVSharpen in v0.8, this is an example of how to use them #202 (comment)

[Blinue]

LumaSharpen and FineSharp are nice sharpening effects, and they are available in v0.8. If you want better performance, use CAS instead