[mod] add 'Accept-Language' HTTP header to online processores

Most engines that support languages (and regions) use the Accept-Language from
the WEB browser to build a response that fits to the language (and region).

- add new engine option: send_accept_language_header

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/google.py

@@ -45,6 +45,7 @@ categories = ['general', 'web']
 paging = True
 time_range_support = True
 safesearch = True
+send_accept_language_header = True
 use_mobile_ui = False
 supported_languages_url = 'https://www.google.com/preferences?#languages'
 
@@ -241,16 +242,6 @@ def get_lang_info(params, lang_list, custom_aliases, supported_any_language):
         # language.
         ret_val['params']['lr'] = "lang_" + lang_list.get(lang_country, language)
 
-        # Accept-Language: fr-CH, fr;q=0.8, en;q=0.6, *;q=0.5
-        ret_val['headers']['Accept-Language'] = ','.join(
-            [
-                lang_country,
-                language + ';q=0.8,',
-                'en;q=0.6',
-                '*;q=0.5',
-            ]
-        )
-
     return ret_val