[Feature]: Add a mask blur function

[JonyTianming]

Expected behavior

It is recommended to add a function of mask edge blur, such as adding a slider bar, which can set the mask edge blur value,Because the edge of the picture pulled out now is a little stiff.

[continue-revolution]

This is already available on the img2img panel. However, it is not available on the txt2img panel. This should be implemented by ControlNet developers, and it should not be too hard. You can submit a feature request there.

If your goal is not for better inpainting, please let me know the use case, and I can see if I should have a try.