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

This ensures that the default value of openstack_release - "auto" - is
handled correctly when deploying bifrost.

Change-Id: I71e6fc5a6b82dc5d6788bf093cd079c45d890ffd

It is not currently possible to deploy Bifrost on a host other than the
Ansible control host. A deployer may want to manage an Ansible control
environment remotely from the Bifrost deployment host but is currently
unable to.

This change adds a new top level 'deployment' Ansible group and a
'bifrost' Ansible group containing the 'deployment' group. The Ansible
play in ansible/bifrost.yml is now targeted at the hosts in the
'bifrost' group. For backwards compatibility, the all-in-one and
multinode inventories add localhost to the deployment group. This allows
a deployer to deploy Bifrost on a remote host by modifying the hosts in
the deployment or bifrost groups.

Change-Id: I76808feab5dd67dff63379ed9c7d08a105636acf
Closes-bug: #1665373

Change-Id: I44c2668a8ebb6dd3201a6eb4e47284871380e6d7

- This change addes the ability to deploy
  and bootstrap bifrost.
- This change introduces a deploy-bifrost
  command to kolla-ansible.

Change-Id: I62afcf348661add900c98904e90a15a0eddffd4b
Implements: blueprint bifrost-support