Supports Kubespray workspace with multiple OpenStack-deployed k8s
clusters.

* Create sample inventory directory for template
* Moved broken `group_vars` symlink to sample directory
* Created sample cluster Terraform file
* Updated documentation

https://www.terraform.io/docs/providers/openstack/r/networking_router_v2.html#external_gateway

Hardcoded variables are removed from variables.tf file because it might
not be suitable for all OpenStack Cloud depending on Identity API
version available (between v2 or v3) and preferred authentication
method.

For distribution who ship python3 as default python, it breaks the
inventory script as it is not compatible with python3.

* Adding bastion and private network provisioning for openstack terraform

* Remove usage of floating-ip property

* Combine openstack instances + floating ips

* Fix relating floating IPs to hosts for openstack builds

* Tighten up security groups

Allow ssh into all instances with floating IP

* Add the gluster hosts to the no-floating group

* Break terraform into modules

* Update README and var descriptions to match current config

* Remove volume property in gluster compute def

* Include cluster name in internal network and router names

* Make dns_nameservers a variable

* Properly tag instances and subnets with `kubernetes.io/cluster/$cluster_name`

This is required by kubernetes to support multiple clusters in a single vpc/az

* Get rid of loadbalancer_apiserver_address as it is no longer needed

* Dynamically retrieve aws_bastion_ami latest reference by querying AWS rather than hard coded

* Dynamically retrieve the list of availability_zones instead of needing to have them hard coded

* Limit availability zones to first 2, using slice extrapolation function

* Replace the need for hardcoded variable "aws_cluster_ami" by the data provided by Terraform

* Move ami choosing to vars, so people don't need to edit create infrastructure if they want another vendor image (as suggested by @atoms)

* Make name of the data block agnostic of distribution, given there are more than one distribution supported

* Add documentation about other distros being supported and what to change in which location to make these changes

* Add comment line and documentation for bastion host usage

* Take out unneeded sudo parm

* Remove blank lines

* revert changes

* take out disabling of strict host checking

* Point apiserver address to 0.0.0.0
Added loadbalancer api server address
* Update documentation

This trigger ensures the inventory file is kept up-to-date. Otherwise, if the file exists and you've made changes to your terraform-managed infra without having deleted the file, it would never get updated. 

For example, consider the case where you've destroyed and re-applied the terraform resources, none of the IPs would get updated, so ansible would be trying to connect to the old ones.

Add resolvconf_mode and cloud_provider config description to README.md

Add section how to configure k8s cluster and set up kubectl

The nova command for getting the flavors is not
nova list-flavors
but
nova flavor-list

Rewrote AWS Terraform deployment for AWS Kargo. It supports now
multiple Availability Zones, AWS Loadbalancer for Kubernetes API,
Bastion Host, ...

For more information see README

Restores working order of contrib/terraform/openstack, includes vault group and avoids group_vars/k8s-cluster.yml

* Leave all.yml to keep only optional vars
* Store groups' specific vars by existing group names
* Fix optional vars casted as mandatory (add default())
* Fix missing defaults for an optional IP var
* Relink group_vars for terraform to reflect changes

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

That way, it will not become stale.

Related bug #929

More recent versions of OpenStack Horizon provide Identity v2 and
Identity v3 versions of the RC file.

Also update reset.yml to do more dns/network related cleanup.