Updated Openstack to terraform 0.12 (#5062)
* update openstack to terraform 0.12(.5)
* replace cluter.tf with cluster.tfvars
* update README.md to terraform 0.12
* update Openstack CI tests to use terraform 0.12
* specify terraform version in openstack README
* gitlab CI to copy cluster.tfvars in case of openstack provider
* The terraform/openstack dynamic inventory can read
tfstate v4 (generated by terraform 0.12) and convert them internally
ro v3 (as generated by terraform 0.11.x).
Additionally the script has been updated to Python 3.
* Add README to bootstrap-os role
* Rework bootstrap-os once more
* Document workarounds for bugs/deficiencies in Ansible modules
* Unify and document role variables
* Remove installation of additional packages and repositories
* Merge Ubuntu and Debian tasks
* Remove pipelining setting from default playbooks
* Fix OpenSUSE not running its required tasks
* bootstrap: rework role
* support being called from a non-root user
* run some commands in check mode
* unify spelling/task names
* bootstrap: fix wording of comments for check_mode: false
* bootstrap: remove setup-pipelining task
* Change deprecated vagrant ansible flag 'sudo' to 'become'
* Emphasize, that the name of the pip_pyton_modules is only considered in coreos
* Remove useless unused variable
* Fix warning when jinja2 template-delimiters used in when statement
There is no need for jinja2 template-delimiters like {{ }} or {% %}
any more. They can just be omitted as described in https://github.com/ansible/ansible/issues/22397
* Fix broken link in getting-started guide
