[mod] botdetection - improve ip_limit and link_token methods

- counting requests in LONG_WINDOW and BURST_WINDOW is not needed when the
  request is validated by the link_token method [1]

- renew a ping-key on validation [2], this is needed for infinite scrolling,
  where no new token (CSS) is loaded. / this does not fix the BURST_MAX issue in
  the vanilla limiter

- normalize the counter names of the ip_limit method to 'ip_limit.*'

- just integrate the ip_limit method straight forward in the limiter plugin /
  non intermediate code --> ip_limit now returns None or a werkzeug.Response
  object that can be passed by the plugin to the flask application / non
  intermediate code that returns a tuple

[1] https://github.com/searxng/searxng/pull/2357#issuecomment-1566113277
[2] https://github.com/searxng/searxng/pull/2357#discussion_r1208542206
[3] https://github.com/searxng/searxng/pull/2357#issuecomment-1566125979

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

searx/botdetection/__init__.py

@@ -9,18 +9,4 @@ The methods implemented in this python package are use by the :ref:`limiter src`
 
 """
 
-import flask
-
-
-def dump_request(request: flask.Request):
-    return (
-        "%s: '%s'" % (request.headers.get('X-Forwarded-For'), request.path)
-        + " || form: %s" % request.form
-        + " || Accept: %s" % request.headers.get('Accept')
-        + " || Accept-Language: %s" % request.headers.get('Accept-Language')
-        + " || Accept-Encoding: %s" % request.headers.get('Accept-Encoding')
-        + " || Content-Type: %s" % request.headers.get('Content-Type')
-        + " || Content-Length: %s" % request.headers.get('Content-Length')
-        + " || Connection: %s" % request.headers.get('Connection')
-        + " || User-Agent: %s" % request.headers.get('User-Agent')
-    )
+from ._helpers import dump_request