* Re-enable ansible_ssh_pipelining as expected for the cluster.yml
* Do not use 'all' wildcasts for hosts, limit only to k8s-cluster, etcd,
  calico-rr groups instead. Other nodes in inventory are out of Kargo
  scope and it's up to users how to manage them.

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

Add BGP route reflectors support in order to optimize BGP topology
for deployments with Calico network plugin.

Also bump version of calico/ctl for some bug fixes.

Some systems (e.g. CentOS on Azure) have requiretty in sudoers which makes
pipelining fail.

In order to enable offline/intranet installation cases:
* Move DNS/resolvconf configuration to preinstall role. Remove
  skip_dnsmasq_k8s var as not needed anymore.

* Preconfigure DNS stack early, which may be the case when downloading
  artifacts from intranet repositories. Do not configure
  K8s DNS resolvers for hosts /etc/resolv.conf yet early (as they may be
  not existing).

* Reconfigure K8s DNS resolvers for hosts only after kubedns/dnsmasq
  was set up and before K8s apps to be created.

* Move docker install task to early stage as well and unbind it from the
  etcd role's specific install path. Fix external flannel dependency on
  docker role handlers. Also fix the docker restart handlers' steps
  ordering to match the expected sequence (the socket then the service).

* Add default resolver fact, which is
  the cloud provider specific and remove hardcoded GCE resolver.

* Reduce default ndots for hosts /etc/resolv.conf to 2. Multiple search
  domains combined with high ndots values lead to poor performance of
  DNS stack and make ansible workers to fail very often with the
  "Timeout (12s) waiting for privilege escalation prompt:" error.

* Update docs.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

This patch provides support for Canal network plugin installation
as a self-hosted app, see the following link for details:

https://github.com/tigera/canal/tree/master/k8s-install

* Don't push containers if not changed
* Do preinstall role only once and redistribute defaults to
  corresponding roles

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Shorten deployment time with:
- Remove redundand roles if duplicated by a dependency and vice versa
- When a member of k8s-cluster, always install docker as a dependency
  of the etcd role and drop the docker role from cluster.yaml.
- Drop etcd and node role dependencies from master role as they are
  covered by the node role in k8s-cluster group as well. Copy defaults
  for master from node role.
- Decouple master, node, secrets roles handlers and vars to be used w/o
  cross references.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

This decreases the time required to deploy a cluster with
3 nodes, but none are standalone etcd roles.

etcd facts are generated in kubernetes/preinstall, so etcd nodes need
to be evaluated first before the rest of the deployment.

Moved several directory facts from kubernetes/node to
kubernetes/preinstall because they are not backward dependent.

This should make things a little more composable,
by making these roles meta roles that perform no
actions by default we allow each role to own its own
resources.

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