Create new promote jobs for infra-index and docs-site.
Also, add promote-openstack-specs job that we can use for publishing
all specs site later.
Add the same file list (copied from openstack-zuul-jobs) for the two
project-config promote jobs.
Remove the now obsolete publish jobs.
Remove now obsolete playbooks.
Needed-By: https://review.opendev.org/682215
Change-Id: I3c227f4229a0572a532009f270d44059698f53e8