* drop the detached gpg signature as this doesn't seem required anymore by
anything; the signed git tag is sufficient to auth the released source

* exclude vagrant data from git clean, otherwise this destroys the test
environment which is useful during the release process; this does not
cause any vagrant artifacts to become part of the release source

* drop attaching release artifacts to milestones, as GitLab Releases
have made this practice deprecated

* add diffoscope command for easier tarball comparison

It doesn't provide info about partitions present on the disk, plus it
duplicates the full hwinfo output when hardware = yes (default)

set to wrap at 1000 columns by default to avoid MTA rejection allowed by
SMTP RFC2821

This is part of a fix for reproducible builds where usrmerge may or may
not be in effect on the build system. We need to be able to pass the
BASH envvar to autotools so its able to correctly determine the correct
path for bash. The lines removed here were added to fix DEBBUG-346303
but should not be required on a clean build environment, where BASH
remains unset unless the current shell is actually BASH, and when it is,
should return the correct path to the bash executable and not /bin/sh.

That way GitLab is able to convert both internal bug ids and Debian bug
tracker numbers to hyperlinks in the rendered version.

Add new restic handler

See merge request !48

Without it, the single-quoted paths on the command-line are interperted
literally, leading restic find all include paths invalid...

Make this consistent with the borg handler. Allows users to use paths
that include spaces in them and prevents shell globbing when the restic
command is called. According to the restic docs, if glob paths are
needed, they should be read from a file (--files-from).