Bug#883321: britney: Add "block-all udeb" support

[Niels Thykier <niels@thykier.net>]

Package: release.debian.org
Severity: wishlist
Tags: newcomer
User: release.debian.org@packages.debian.org
Usertags: britney

Wishlist item:

Currently a d-i freeze involves blacklisting packages with
udebs. However, Britney should have enough information to determine
which packages have udebs and thereby support a "block-all udeb". This
would enable us to freeze all udebs.


(Originally filed as: https://github.com/Debian/britney2/issues/21)

Thanks,
~Niels