Propose solution to count and monitor log events in CTA (instrumentalization)

In CTA, we should be able to count how many times different event occur and publish this information to monitoring.

Some use-cases:

• Count how many times different DB queries were performed (such as in #155 (closed)).
• etc...

Some requeriments:

• Generic solution, for all log event counting use-cases.
• Publish periodically all the collected metrics for monitoring (for exemple, by writting to the log in json).
• Allow some context to be passed to the counters (for example as multiple dimensions { X.Y.Z.metric_name = 1 }).