Add custom events to support analytics

A common requirement on faceted searches is to push changes in the search query to an analytics layer so site owners can understand how search is being used. To support this the search root and components should fire custom events when changes are made so that developers can listen for the events and pass them to the analytics layer.

To Do

• Determine if all events should originate from the search-root or individual components
• Identify types of events
• Identify context/info that should be provided in the events