search: facets by collection adaptation

* Adds fixtures for inspire.

* Adds inspire collection facet which use 980__a MARC field via
  bibfield collection key.

* Introduces PACKAGES_FACETS_EXCLUDE config variable to disable
  import of unneeded facets.

Signed-off-by: Kamil Neczaj <kamil.neczaj@gmail.com>
base: removal of Collectionname fixtures

* NOTE The fixtures are not needed because their
  content is loaded from CollectionData fixture.
  Beside this the fixture was never loaded
  because of lack of the corresponding model.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>