Backlog/112 alarms

Adds an Alarm document, finishing the issue https://github.com/telefonicaid/fiware-connectors/issues/112

It also adds new INFO traces needed by the alarm system.

A minor fix in the README has been done as well.
Fixed in https://github.com/telefonicaid/fiware-connectors/commit/d722c5c767c526d53da989c77993f0a4d7978b59