deposit: updates CrossRef import fields mapping

* Updates the fields for the CrossRef Flask extension.

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>
deposit: 'status' key update

* See inveniosoftware/invenio#2024 and inveniosoftware/invenio@ffb60c3.

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>
deposit: 'page_nr' MarcXML mapping

Signed-off-by: Pedro Gaudêncio <pedro.gaudencio@cern.ch>