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