issues 449,448 remove_cluster.yml improvements

[rrrru]

@vitabaks vars -> default(false), blocks for dry, remove systemd file cuz consul role do not restart service if exist
#449

[rrrru]

@vitabaks I set 'ignore_errors' because the task crashes when restarted.

[vitabaks]

@rrrru thanks!

I see that you decided not to add the task 'consul kv delete', why?

[rrrru]

@rrrru thanks!

I see that you decided not to add the task 'consul kv delete', why?

At first I had wrong idea what the problem was.
It turned out that the problem was in the scope to which the task was distributed (postgre_cluster). So I added another group for conusl and specified consul_instances in hosts.