Joex imports unnecessary embedded images from HTML messages on "Import only attachments"

Hi!

Sometimes I get HTML mails with PDF invoices and embedded images (logs from the companies). Joex imports the image and the PDF. But the image is really not needed. Embedded images in mails usually have a special identifier in the MultiMimePart header (cid:random-number). It would be very useful if these are filtered out during import. In Docspell it is very time-consuming to delete the superfluous images of a mail import and in addition the embedded graphics are always displayed first, but not the interesting attachments.