Rewrite bin/make-package to use git-buildpackage
We now use git-buildpackage to build our packages.
bin/make-package
should be changed to use this workflow.
As it's a non-trivial piece of code, it would be worth rewriting it in Python at the same time.
(This task replaces #1141 (closed).)
Migrated from T1555 (view on Phabricator)