[mod] settings.yml can be /etc/searx/settings.yml

The exact order is
* first from SEARX_SETTINGS_PATH,
* if not found then from searx code base,
* if not found then from /etc/searx/settings.yml
* if not found an exception stops searx loading

searx/utils.py

@@ -186,9 +186,9 @@ def get_resources_directory(searx_directory, subdirectory, resources_directory):
     return resources_directory
 
 
-def get_themes(static_path):
+def get_themes(templates_path):
     """Returns available themes list."""
-    themes = os.listdir(os.path.join(static_path, 'themes'))
+    themes = os.listdir(templates_path)
     if '__common__' in themes:
         themes.remove('__common__')
     return themes