There is a future requirement for Spyglass to have helm charts. These
charts will need docker images published in a source countrolled
manner.
This change depends on https://review.opendev.org/#/c/657614/ which
adds the airship_spyglass_quay_creds parameters. This patch:
1. Adds the docker-image-build playbook for Spyglass.
2. Uses the playbook in zuul jobs: check, gate and post.
3. Adds the spyglass-single-node nodeset.
4. Adds the vars.yaml file required by docker-image-build playbook.
5. Adds the image_tags.py script required by docker-image-build
playbook.
6. Adds the docker-systemd.conf file required by docker-image-build
playbook.
Change-Id: I76981e719a7e42984089fec08e1161a6923c5c52
b9f2ce32b3