dh_listpackages: Package-Type: udeb implies Build-Profiles: <!noudeb>

Many packages that build udebs, can do so with pure dh sequencer alone. Many udeb packages only declare package type udeb, and do not declare any build-profiles. This makes them not support noudeb build profile. However, it would be really nice if they did. To speed up dh_builddeb / upload especialy when udebs are discarded and not needed in the end. Also doing this in debhelper will save everyone sprinkling those all over the archive (i.e. the dozens and dozens of d-i packages components).

This may cause a small minority of packages to FTBFS, thus adding this in the next compat level might be best.

Also not sure if this needs Policy wording changes too or not.