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.
I agree (as additional argument, the base README.md should be simple... basically building and running instruction, along with references to other pieces or more detailed information, such as this stuff about log and alarms for operators).