`youtube_api.py` throws an exception if the search results contain a channel, as
channels have no videoId. This PR adds a keycheck for parsing the json response.
Embedded HTML breaks SearXNG architecture. To modularize, HTML is generated in
the templates (oscar & simple) and result parameter 'embedded' is replaced by
'data_src', an URL for embedded content (<iframe>).
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
The language_support variable is set to True by default,
and set to False in only 5 engines.
Except the documentation and the /config URL, this variable is not used.
This commit remove the variable definition in the engines, and
set value according to supported_languages length: False when the length is 0,
True otherwise.
Close#2485