search: new facets gui engine

This pull request is to make a configurable gui for facets with intension to make it work later with Elastic Search.
I don't see the reason.

facet-list updates it's state and sends the information with 'updated' event. The reaction of the SearchResultsPage class is to update the search field, store facets state in the address bar, and update the results.

I try to actually encapsulate the invenio query inside SearchResultsPage, and limit its usage to set the search field and to query the server for the results. If one wants to get the changed state they should also attach the code to 'updated' event of facets.