WebSearch: better retrieval of record tabs

 * When retrieving the tabs for the detaild record pages,
   use the guess_collection_of_a_record() function that
   also takes into account the referer. (addresses #2068)

Signed-off-by: Ludmila Marian <ludmila.marian@gmail.com>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebSearch: improve detection of record owners

* If CFG_CERN_SITE, consider the possibility of the owner
  of a record being an egroup, defined as 'foo@cern.ch'
  insted of 'foo [CERN]'. (addresses #2068)

Signed-off-by: Ludmila Marian <ludmila.marian@gmail.com>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebSearch: CERN-specific lecture latest additions

* CERN-specific selection of records to populate the latest
  additions for the lectures collections. (addresses #2068)

Signed-off-by: Ludmila Marian <ludmila.marian@gmail.com>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebSearch: CERN-specific video latest additions

* CERN-specific selection of records for the latest additions
  of the videos collections. (closes #2068)

Signed-off-by: Ludmila Marian <ludmila.marian@gmail.com>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>