Add 'dummy package' and 'dependency package', the other phrases the
Debian Developer's Reference (6.9.7) documents as convention and that
deborphan --guess-dummy looks for. Deliberately skip bare 'dummy' and
'empty package': both have real false positives in production data
(xserver-xorg-video-dummy, a bridge card 'double dummy solver'
library, python3-roscreate's 'empty package template creator').
Verified against production data: 266 combined matches, still zero
with screenshots.
Their short description reliably says so (e.g. 'transitional
package', 'transitional dummy package for foo'). Verified against
production package data: 190 matches, none of them ever had a
screenshot.
Libraries never produce useful screenshots. Excluding by Debian
archive section instead of a lib* name pattern keeps applications
with lib-prefixed names (libreoffice, librecad, ...) importable.
With REMOVE_BLACKLISTED_PACKAGE set, the next import also removes
previously imported libs-section packages and their screenshots.
