Please disable default image sharpening in the VIPS backend

[pyridine]

Hi, this is related to carrierwaveuploader/carrierwave#2481 and #67
Default image sharpening was disabled a while back in the ImageMagick backend, but not in the VIPS backend. I think it should be disabled by default in both. The default sharpening behavior is not expected and can degrade/change the image quality.

Here are the results of resizing an image in VIPS vs ImageMagick:

Base image

Converted with ImageMagick backend

Converted with VIPS backend

As with the original issue, the ImageMagick-processed image has not changed (much?), while VIPS-processed image appears lower quality, or at least different, which is not expected.

I used this code:

processed = ImageProcessing::Vips # or MiniMagick
  .source(base_image)
  .resize_to_fit(1280,720) # the image is already this size, so this shouldn't change anything
  .convert("png")
  .call