Sync project-config to remote host

This syncs the ``project-config`` repo checked out on the bastion host
(which is actually running the Ansible that runs this role) to the
current host.  This repo holds configuration for some production hosts
and thus we want to make sure to deploy those services with the
checked-out tree Zuul has prepared for a given deploy-pipeline CD job
run (i.e. so we apply config updates in commit order).

Also see the `setup-src
<https://opendev.org/opendev/base-jobs/src/branch/master/playbooks/infra-prod/setup-src.yaml>`__
to see where this checkout is setup; there are some tricks -- for
example for hourly and periodic jobs we want to ensure we run from
master at the time the job runs, not at the time the job was enqueued.