check HTTP response:
* detect some comme CAPTCHA challenge (no solving). In this case the engine is suspended for long a time.
* otherwise raise HTTPError as before
the check is done in poolrequests.py (was before in search.py).
update qwant, wikipedia, wikidata to use raise_for_httperror instead of raise_for_status
This change is backward compatible with the existing configurations.
If a settings.yml loaded from an user defined location (SEARX_SETTINGS_PATH or /etc/searx/settings.yml),
then this settings can relied on the default settings.yml with this option:
user_default_settings:True
Alexandre Flament
Adam Tauber