The entire source code of the duckduckgo engine has been reengineered and
purified.
1. DDG used the URL https://html.duckduckgo.com/html for no-JS requests whose
response is also easier to parse than the previous
https://lite.duckduckgo.com/lite/ URL
2. the bot detection of DDG has so far caused problems and often led to a
CAPTCHA, this can be circumvented using `'Sec-Fetch-Mode'] = “navigate”`
Closes: https://github.com/searxng/searxng/issues/3927
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
b183e620d8