* Add restart for weave service unit
* Reuse docker_bin_dir everythere
* Limit systemd managed docker containers by CPU/RAM. Do not configure native
  systemd limits due to the lack of consensus in the kernel community
  requires out-of-tree kernel patches.

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

Also place in global vars and do not repeat the kube_*_config_dir
and kube_namespace vars for better code maintainability and UX.

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

The Jinja2 filter 'reverse' returned an iterator instead of a list,
resulting in the umount task to fail.

Intead of using the reverse filter, we use 'tac' to reverse the output
of the previous task.

This deletes everything related to the cluster and allows to start from
scratch.