In order to be able to redirect list addresses which have moved from
one domain to another, we need a solution to alias the old addresses
to the new ones. We have simple aliases but they only match on the
local part. Add a new /etc/aliases.domain which matches full
local_part@domain addresses instead. Also collect this file in the
Mailman deployment test for ease of inspection.
Change-Id: I16f871e96792545e1a8cc8eb3834fa4eb82e31c8