OPC-UA Listener plugin support for Events

Would be nice to be able to subscribe to events (alarms) as well as data values.
Generally speaking, you subscribe to OPC UA Events similarly to data changes, but by using monitoring parameters that contain an event filter instead of data change filter. Besides the DataChangeFilter property, the UAMonitoringParameters class also has an EventFilter property (of UAEventFilter type).

Start at the OPC-UA Listener plugin and compare its existing data-value subscription flow with the UAMonitoringParameters and UAEventFilter references in the issue. Determine how event alarms should be subscribed alongside data changes, then verify that event notifications are collected as metrics or logs without regressing data-value subscriptions.

Written by the indexing model from the issue text.