Do not build facets for every request

At this moment we always initiate every facet on every request, even if that request does not have any active facet source.
This is intended, as we support showing facets with property only_visible_when_facet_source_is_visible set to false to load on any page.

However, we do not check early enough for this property, which makes us build every facet anyway and trigger for example every url processor for every facet on every page.