Added flag for notification listener visibility

Returns ProbeParameterFactory from ProbeMCOFactory

Removes KPI calculator from probe factory

(cherry picked from commit 366edeb854acb34b05b5169f8c492dda7c433fe5)

Fix for incorrect name extraction in the MCO delivery event

Renamed trait ExecutionLayer.data_source_models to data_sources

Better name to keep consistency with the other entities.

Introduced ExecutionLayer object to simplify notification handling

Allow KPIs to be specified as datasource outputs.

Renamed kpi to is_kpi

Boolean flag on the OutputSlotInfo renamed to is_kpi

Fixes incorrect filename for InputSlotInfo

Added new flag is_kpi to DataValue