i08t01: Don Corleone: add simple metrics

[kudkudak]

Extended description: add very simple metrics collection functionality to don corleone, just to enable tracking how are services working.

API: push_metric(metric_name, value)
:show_metrics(path)

metric_name is service_name.<any_path> for instance
spidercrab.fetched

path will just match regex for instance spidercrab will fetch all metrics pushed by spidercrab.

Time estimation: 2h

[kudkudak]

There is working RabbitMQ+Logstash+Kibana - I think it can efficiently show metrics, so this task will be more about learning how to do it with exisiting things