Since we use the release name as the default tag to publish images
to Dockerhub, we should use this by default.

This change also removes support for the magic value "auto".

Change-Id: I5610cc7729e9311709147ba5532199a033dfd156
Closes-Bug: #1843518

We copy-paste the same play into various playbooks to detect
openstack_release. This change factors that code into a separate
playbook that is imported.

Change-Id: I5fea005642b960080bf5e43455618dc24766c386

Change-Id: Icb9b097299011cc09f3012bbee9629a5457c920c
Closes-Bug: #1681316

Change-Id: I44c2668a8ebb6dd3201a6eb4e47284871380e6d7

This playbook only matters for multinode since AIO can recover from
power outage without additional configuration.

DocImpact
Implements: blueprint mariadb-lights-out
Change-Id: I903c3bcd069af39814bcabcef37684b1f043391f