Added new conf variable CFG_WEBSEARCH_SPLIT_BY_COLLECTION, making the "split by collection" feature configurable.
Added new conf variable CFG_WEBSEARCH_SPLIT_BY_COLLECTION, making
the "split by collection" feature configurable.

tiborsimko/invenio-records,tiborsimko/invenio-search,tiborsimko/invenio-records,tiborsimko/invenio-search,inveniosoftware/invenio-search,inveniosoftware/invenio-records,inveniosoftware/invenio-records,inveniosoftware/invenio-search