Introduce daconfiscate

daconfiscate was previously ran before the source package was built.
This is not only wrong (because it is an automated process on source
code), in order to use it with git-buildpackage, one would have to
commit the confiscation to the checkout, and that is messy.

Because of that, I am placing it into this package, since daconfiscate
shall become obsolete and unused at the same time as aclocal, and they
are the parts of the same story anyways.