WebSearch: optimise can-see-hidden-MARC-tags check
WebSearch: optimise can-see-hidden-MARC-tags check

* Optimises can-see-hidden-MARC-tags check.  Before, the check was done
  by calling RBAC engine on-the-fly for every record.  This patch moves
  the check onto login time and stores the result in user_info object
  so that it is rapidly reused at search time without further querying
  of the database.

  This greatly reduces the number of SQL queries on the search results
  pages.  For an example search page, the number of SQL queries went
  down from about 360 to about 230.

inspirehep/invenio-accounts,tiborsimko/invenio-accounts,inveniosoftware/invenio-accounts,inveniosoftware/invenio-accounts,inveniosoftware/invenio-accounts,tiborsimko/invenio-accounts,tiborsimko/invenio-accounts,inspirehep/invenio-accounts,inspirehep/invenio-accounts