WebSearch: kwalitee fix

* Runs `autopep8` on `websearch_services_regression_tests.py`

Signed-off-by: Federico Poli <federico.poli@cern.ch>
WebSearch: new service JournalHintService

* Adds the search service JournalHint, that displays 'Were you
  looking for a journal reference? Try: <link>' when the user
  search for a raw journal reference.

* Adds regression tests to WebSearchServicesJournalHintService.

Signed-off-by: Federico Poli <federico.poli@cern.ch>