This is a follow up to commit 4ee93922, which introduced partial
deployments.

The unstash operation also needs to be handled specially, as it may
now fail attempting to unstash an item that could not be stashed
previously.

* Jenkinsfile ('Sign & deploy packages'): Skip target deployment when
it fails to be unstashed.

Change-Id: I59341e4c3bb007125402f4b28979d0e8e963757d

When a packaging target fails to build, deploy the successful builds
to the repository anyway.

* Jenkinsfile (BUILD_OWN_QT): Remove parameter.  The Qt builds are now
implicitly made as part of the regular packaging targets.
(Build packages): Wrap make invocation in a catchError so that the
stage appears as failed while the build is marked as a success, which
allows the 'Sign & deploy packages' stage to run despite packaging
errors.

Change-Id: I5785d154f5e1963aa824576f7f0f62043446456a

* Jenkinsfile (properties): New definition.

GitLab: jami-packaging#98
Change-Id: I3406f20027cafe8ab6a5743860b470d92e8455cb

* Jenkinsfile (Deploy packages): New stage.

GitLab: jami-packaging#98
Change-Id: I36a555312e0569549316370878244c3267f8149a

* Jenkinsfile (submodules): New variable.
[parameters]{WITH_MANUAL_SUBMODULES}: New parameter.
(Fetch submodules): Adapt the message to the parameter's value.  Add
the '--remote' option to 'git submodule' unless WITH_MANUAL_SUBMODULES
is true.

GitLab: jami-packaging#98
Change-Id: Ie5f0521bed16303e751e8e19174f18a90bccefcc

The default is to build all the packaging targets (minus the *_qt
and *_arm ones).  Add a PACKAGING_TARGETS parameter that allows
specifying which targets to build.

* Jenkinsfile: (PACKAGING_TARGETS): New parameter.
('Build packages'): Use it unless it's the empty string.

GitLab: jami-packaging#98
Change-Id: Idf1b4460a0edac7cbe6a82b9db1d204af78de801

When a .tarball-version file containing the version string is present,
it is taken for granted that the source tarball is present.  This
allows to lift the requirement on a Git checkout to use the source
tarball.  This makes it easy and cheap to sync this tarball and
accompanying .tarball-version file across different Jenkins agents to
distribute the packaging jobs, bring the total build time from about 1
h 40 to 40 minutes.

* Makefile (TARBALL_VERSION): New variable.  When defined, do not do
not invoke Git to derive the version string, simply use it.
[RELEASE_TARBALL_FILENAME]: Do not compute prerequisites when
TARBALL_VERSION is defined; assume the tarball is present.
* .gitignore: Ignore .tarball-version.
* Jenkinsfile: (Generate release tarball): Generate a .tarball-version
file, and stash it along the release tarball.  Explicit this should
run on a 'guix' agent.
(Build packages): Forward to any 'linux-builder' agent, clean the
workspace, unstash and extract the tarball and build.

GitLab: jami-packaging#98
Change-Id: I13088b75c9ccd5166662a84b7c5f8d4e8b7b65da

* Jenkinsfile [parameters]: New directive.
(Build packages): Skip building custom Qt or ARM packages depending on
the parameter values.

GitLab: jami-packaging#98
Change-Id: Ic68af873483ac92319061baf5f14ef7323a27a26

The phony tarball-producing targets will now always clear the
tarballs.manifest file before generating a new release tarball,
ensuring it doesn't contain stale information.

A new 'portable-release-tarball' target is also added to offer an easy
to use target that was previously implemented ad-hoc in the CI.  Move
this logic here as a portable release tarball is useful for packagers
wanting to test locally with the various supported platforms.  The
Jenkinsfile now makes use of it.

* Makefile (daemon/contrib/native/Makefile): New target.
(tarballs.manifest): Add the above target as a prerequisite and remove
invocation to bootstrap script.  Invoke make with --no-print-directory
to prevent entering/leaving directory messages from appearing in the
output (it's supposed to be on when using --silent, but when the make
invocation is nested, it doesn't seem to be the case).
(release-tarball): Also clear the tarballs.manifest when invoked.
(purge-release-tarballs, portable-release-tarball): New targets.
* guix/minimal-manifest.scm: New file.
* Jenkinsfile ('Generate release tarball): Use it to spawn the
container used to build the release tarball.  Also expose /usr/bin/env
in the container.  Use the new 'portable-release-tarball' target to
simplify things.  Fix the shebang line; it needs to be the first line
of the script.

GitLab: jami-packaging#98
Change-Id: I3b55e25933108ae9930bc9fcc867f9fa51d796f2

The pipeline code is modernized to use the declarative pipeline DSL of
Jenkins, and the GNU/Linux package builds now all share the same
source release archive, which is built from cached contribs tarballs
when available.

GitLab: jami-packaging#55
Change-Id: Id7f37966dd80c36cfa0ebdd461c0ab90505dcd37