WebSearch: kwalitee fix

* Runs `autopep8` on `websearch_services_regression_tests.py`.
  (PR #2352)

Signed-off-by: Federico Poli <federico.poli@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>
WebSearch: new Journal Hint Service

* Adds the Journal Hint Service, that displays
  'Were you looking for a journal reference? Try: <link>'
  when the user search for a raw journal reference.
  (PR #2352)

* Adds unit and regression tests for the new search service.

* Adds two unit tests to `search_from_reference`, just to be sure that
  it accepts unicode.

Signed-off-by: Federico Poli <federico.poli@cern.ch>
Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebSearch: smarter journal hint

* Improves the JournalHintService implementation by directly
  a brief representation of a record when one is found.
  (PR #2352)

* Additionally, suggests to use find rawref "foo" when "foo"
  is searched for, rather than journal:"bar".

Signed-off-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>