Add Kindle Book Format mime-type
Mime-type from: https://www.iana.org/assignments/media-types/application/vnd.amazon.mobi8-ebook Alias from: https://github.com/kovidgoyal/calibre/commit/ddca079000ffd03611d19c5dfe29341b9c1c6e2e#diff-64773d34b80f6772011eb6c82d9fa5ddR37