This moves the official Debian packaging into ring-project. Jenkins
should now be able to run packaging jobs and publish packages. It
should also make it easy to add a `verify` check on Jenkins to test
This will make it much easier to work on packaging issues because the
build environment is now reproductible on any machine.
The patch adds Makefile targets to create packages such as:
Builds are all done inside Docker containers and it is possible to
build many at a time with the `package-all` target.
To debug a build, use `package-<DISTRO>-interactive` to obtain a shell
inside a container, ready to launch a build.