whitelist_ratelimiter: @dalf patch

- it calls ip_address and ip_network only once for the settings.
- init_whitelist to make tests easier
- get_remote_addr get the IP address for the function is_accepted_request
- for reference: https://esd.io/blog/flask-apps-heroku-real-ip-spoofing.html

manage

@@ -698,6 +698,7 @@ test.pylint() {
         build_msg TEST "[pylint] searx tests"
         python ${PYLINT_OPTIONS} ${PYLINT_VERBOSE} \
             --disable="${PYLINT_SEARXNG_DISABLE_OPTION}" \
+            --additional-builtins="${PYLINT_ADDITIONAL_BUILTINS_FOR_ENGINES}" \
 	    --ignore=searx/engines \
 	    searx tests
     )