search: "Error: Validation error." when filtering with the "years" facet

[nharraud]

Related to inveniosoftware/invenio-app-ils#37

Problem:
Requesting a "time" facet as range will still display it as a checkbox widget. This creates an error as invenio-search expects either a range query or a terms query but not both at the same time.

Temporary solution for modules using invenio-search-js:
Show only one of the widgets in the template.

Solution for invenio-search-js:
Detect automatically that the facet is a range facet or not and use the right widget.