Provide yaml setup files for usage with jenkins-job-builder

NOTE: I've filed a report against upstream's BTS to (hopefully)
get a new release of jenkins-job-builder, see
https://bugs.launchpad.net/openstack-ci/+bug/1251201
In the meanwhile be aware that the unsupported settings
(see jjb/README for details) are just ignored.

The piuparts job currently doesn't work out-of-the-box when set up
via jenkins-job-builder without the patch from
https://review.openstack.org/#/c/56412/ because the CopyArtifact
plugin applies a rewrite of the config.xml on first *build* of
the Jenkins job.