[enh] engine - add Tineye reverse image search

Other optional parameter ..

`&sort=crawl_date`
    can be appended to search_string to sort results by date.

`&domain=example.org`
    can be implemented to search_string to get results from just one domain.

Public instances could get relatively fast timed-out for 3600s.

--

Merged from @allendema's commit [1] and slightly modfied / see [2].

Related-to: [1] https://github.com/allendema/searx/commit/455b2b4460cd830ac1f7e62e824040e2fe648de9
Related-to: [2] https://github.com/searx/searx/pull/3040


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