Introduce navigator and faceted search configuration

[mcolacino]

1. Allow to configure the widget title (default: 'related articles')
2. Allow to decide to hide facets displaying a toggle button instead (default: visible)

[cyberandy]

This is issue has been clearly brought up in the testing with Appartamento9. The need is to have a simpler visualization aligned with Taboola and Outbrain (see below)

[cyberandy]

For the Faceted Search Widget the requirements (as per #261) are:

• reducing the number of entities displayed in the list by choosing the most relevant in a given context
• add a show/hide toggle switch (as in the previous version of this widget) to keep the widget as compact as possible

[mcolacino]

The first point is covered by #263 and included in WL 3.4.0