Automatically define Kolla Ansible tag variables in globals.yml

Use the new kolla-images.py script to automatically define tag variables
in globals.yml based on the tags that are defined in kolla_image_tags.

etc/kayobe/kolla/globals.yml

@@ -10,16 +10,21 @@ enable_docker_repo: "{% raw %}{{ 'overcloud' not in group_names or ansible_facts
 # This is necessary for os migrations where mixed clouds might be deployed
 kolla_base_distro: "{% raw %}{{ ansible_facts.distribution | lower }}{% endraw %}"
 
+# Convenience variable for base distro and version string.
+kolla_base_distro_and_version: "{% raw %}{{ kolla_base_distro }}-{{ kolla_base_distro_version }}{% endraw %}"
+
 # Dict of Kolla image tags to deploy for each service.
 # Each key is the tag variable prefix name, and the value is another dict,
 # where the key is the OS distro and the value is the tag to deploy.
 # NOTE: This is defined in etc/kayobe/kolla-image-tags.yml.
 kolla_image_tags:
 {{ kolla_image_tags | to_nice_yaml | indent(width=4, first=true) }}
 
-openstack_tag: "{% raw %}{{ kayobe_image_tags['openstack'][kolla_base_distro] }}{% endraw %}"
-bifrost_tag: "{% raw %}{{ kayobe_image_tags['bifrost'][kolla_base_distro] }}{% endraw %}"
-ovn_tag: "{% raw %}{{ kayobe_image_tags['ovn'][kolla_base_distro] }}{% endraw %}"
+# Variables defining which tag to use for each container's image.
+{{ lookup('pipe', 'python3 ' ~ kayobe_config_path ~ '/../../tools/kolla-images.py list-tag-vars') }}
+
+#############################################################################
+# RabbitMQ
 
 om_enable_rabbitmq_high_availability: true