collections: module separation
collections: module separation

* INCOMPATIBLE Separates collections module to independent
  Invenio-Collections package. (addresses #3233)

Signed-off-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

tiborsimko/invenio-base,inveniosoftware/invenio-base,tiborsimko/invenio-base,inveniosoftware/invenio-base