search: fix query string in add-to-search

* Adds double quotes around author and title value. (closes #2251)

* Splits terms by whitespace or quotes and join them
  with proper operator. (addresses #2252)

Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>