Realesrgan

- Replace RealESRGANv2-animevideo model with realesr-animevideov3 model.
- Change the default of model to 3.

- Switch to ONNX Runtime for inferencing.
- Rename `model_type` parameter to `model`.
- Rename `tile_x`, `tile_y` parameters to `tile_w`, `tile_h`.
- Remove `pre_pad` parameter.

- Add a check to make sure model files have been downloaded.
- Only VS API4 is supported now.
- Add support for RealESRGANv2-animevideo models.
- Remove `scale` and `anime` parameters.
- Add `model_type` parameter.

- Change `tile` parameter to `tile_x` and `tile_y`.
- Add support for VS API4.

- Add model optimized for anime.
- Rename `half` parameter to `fp16` for intuition.

Please be aware that this is a pre-release. There may be bugs to be fixed, so feel free to open a new issue when you encounter one.
This pre-release contains the following bug fixes:
- Fix Format24bppRgb image not being handled properly.
- Fix not doing premultiplied alpha before saving the image with an alpha channel. (This may cause some software to have weird artifacts, especially some that do not support straight alpha mode.)