Downgrade coredns to 1.6.5 due to upgrade errors while migrating coredns configmap (Corefile) (#5960)

cloud_provider option exists in ./inventory/sample/group_vars/all/all.yml
In addition, the quick start shows to create configuration by copying
./inventory/sample. So this updates path of all.yml for fitting the above.

* Add proxy support to CRI-O service

The crio.service requires proxy environment variables when it's
deployed behind a corporated network. This change creates a systemd
configuration file when the proxy variables are defined.

* Remove unnecesary crio's tasks

* Fix kube-proxy ds nodeselector for older versions

* Fix for ansible-lint

* Gather just the necessary facts

* Move fact gathering to separate playbook.

The playbook that bootstrap openSUSE servers assumes that the
/etc/sysconfig/proxy file exists but the execution fails when
these file is not present. This change guarantees its existence.

https://github.com/colemickens/azure-kubernetes-status is deprecated
and will be removed soon as the README.
So this updates the link to the repository for a new one.

The Terraform installation part states that is for CentOS 7, but the echo command refers to OS X binary. Updated the echo command to use the Linux version.

* Terraform/OpenStack: Allow free form worker node definition

* fixup! Terraform/OpenStack: Allow free form worker node definition

* assembly fallback_ips and no_proxy var only one time on localhost and populate result on all hosts

* add tag always, fix ansible lint errors

* workaround to mitogen issue dw/mitogen#663

* do not gather fact before install python on coreos like distros

* try to pass docker molecule test

* Generate unique username per cluster

* rename admin kubeconfig shell output to raw_admin_kubeconfig

* Make the linter happy

* Fix lint errors

* Cleaning up tasks

* Add Molecule for container-engine/docker

* Add bootstrap-os to Molecule prepare stage

* Customize PodSecurityPolicies from inventory

* Fixed yaml indentation

* Add CI_TEST_VARS to tests

* Update flannel to 0.12.0 (with new manifests) and disable tx/rx
offloading in networking test

Add the `container_manager` variable as a Cluster Variable in the global Docs