Add progressive encoding to JpegBitmapEncoder

While the `PngBitmapEncoder` offers an [`Interlace`](https://docs.microsoft.com/en-us/dotnet/api/system.windows.media.imaging.pngbitmapencoder.interlace) property to enable such encoding, there's no such property available for [`JpegBitmapEncoder`](https://docs.microsoft.com/en-us/dotnet/api/system.windows.media.imaging.jpegbitmapencoder), although the JPEG specification does offer such technology, called `progressive encoding` .

Please, can we get that implemented in `System.Windows.Media.Imaging.JpegBitmapEncoder`, too? 🥺

Start with System.Windows.Media.Imaging.JpegBitmapEncoder and compare its public API with PngBitmapEncoder.Interlace, then trace the JPEG encoding implementation and existing encoder tests. Done means exposing a progressive-encoding option for JPEG output and covering it with tests that verify progressive JPEG encoding.

Written by the indexing model from the issue text.