[fix] python searxng_extra/standalone_searx.py --help

The scripts loads the engine and then parse the arguments.
After that the engines are initialized.

Before this commit, with "--help", the HTTP clients are closed before
the engine initialization threads. When these init threads try to send
an HTTP request, an exception is raised.

searxng_extra/standalone_searx.py

@@ -196,9 +196,14 @@ def parse_argument(
 
 
 if __name__ == '__main__':
-    searx.search.initialize()
+    settings_engines = searx.settings['engines']
+    searx.search.load_engines(settings_engines)
     engine_cs = list(searx.engines.categories.keys())
     prog_args = parse_argument(category_choices=engine_cs)
+    searx.search.initialize_network(settings_engines, searx.settings['outgoing'])
+    searx.search.check_network_configuration()
+    searx.search.initialize_metrics([engine['name'] for engine in settings_engines])
+    searx.search.initialize_processors(settings_engines)
     search_q = get_search_query(prog_args, engine_categories=engine_cs)
     res_dict = to_dict(search_q)
     sys.stdout.write(dumps(