* monitoredTarget in monitoring rules had "id" renamed to "type" because
of its ambiguity. From now on:
  * "class" specify the resource according to the
[ontology](https://github.com/deib-polimi/modaclouds-qos-models/blob/master/doc/user-manual.md#the-monitoring-ontology)
  * "type" is the name assigned to a resource during the design phase,
univocally identifying the role of the resource
  * "id" (currently not available in monitoring rules) is the unique
identifier of a deployed instance
* installation instructions updated (look at the documentation)
Merge branch 'master' of https://github.com/deib-polimi/modaclouds-qos-models.git