[mod] engine duckduckgo - use DuckDuckGo-Lite

Implement a scrapper for DuckDuckGo-Lite [1].  The existing DuckDuckGo [2]
engine does not support paging.  DuckDuckgo-Lite is much faster, less verbose
and does have a paging option (reversed engineered from the input form of [1]).

[1] https://lite.duckduckgo.com/lite
[2] https://duckduckgo.com/



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