This adds another script to detect and remove more low-quality thu-
mbnails. For example:
- If an item has an "IM Thumbnail" and a "Generated Thumbnail" in the
THUMBNAIL bundle, remove the "Generated Thumbnail"
- If an item has a PDF bitstream and a JPEG bitstream with a name or
description "thumbnail" in the ORIGINAL bundle, remove the
"thumbnail" bitstream in the ORIGINAL bundle and try to remove the
"thumbnail.jpg" bitstream in the THUMBNAIL bundle
The idea is that we should *always* prefer thumbnails generated by
ImageMagick from PDFs in the ORIGINAL bundle and should remove any
other manually uploaded thumbnails.