[mod] replace engines_languages.json by engines_traits.json

Implementations of the *traits* of the engines.

Engine's traits are fetched from the origin engine and stored in a JSON file in
the *data folder*.  Most often traits are languages and region codes and their
mapping from SearXNG's representation to the representation in the origin search
engine.

To load traits from the persistence::

    searx.enginelib.traits.EngineTraitsMap.from_data()

For new traits new properties can be added to the class::

    searx.enginelib.traits.EngineTraits

.. hint::

   Implementation is downward compatible to the deprecated *supported_languages
   method* from the vintage implementation.

   The vintage code is tagged as *deprecated* an can be removed when all engines
   has been ported to the *traits method*.

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

searx/webutils.py

@@ -1,4 +1,6 @@
 # -*- coding: utf-8 -*-
+from __future__ import annotations
+
 import os
 import pathlib
 import csv
@@ -8,7 +10,7 @@ import re
 import inspect
 import itertools
 from datetime import datetime, timedelta
-from typing import Iterable, List, Tuple, Dict
+from typing import Iterable, List, Tuple, Dict, TYPE_CHECKING
 
 from io import StringIO
 from codecs import getincrementalencoder
@@ -16,7 +18,10 @@ from codecs import getincrementalencoder
 from flask_babel import gettext, format_date
 
 from searx import logger, settings
-from searx.engines import Engine, OTHER_CATEGORY
+from searx.engines import OTHER_CATEGORY
+
+if TYPE_CHECKING:
+    from searx.enginelib import Engine
 
 
 VALID_LANGUAGE_CODE = re.compile(r'^[a-z]{2,3}(-[a-zA-Z]{2})?$')