liveleak.lua: Improve support for 3rd party embedded content

Some of the videos may be hosted elsewhere, if that appears to be the
case, then try to parse the relevant (embedded) media URL from the page
HTML.  Leave it for libquvi to determine whether the media URL can be
parsed.

Signed-off-by: Toni Gundogdu <legatvs@gmail.com>
tests: resolve.t: Add a test for liveleak

* Update resolve.t with a test for liveleak.lua
* Add redirect_url_liveleak.json

Signed-off-by: Toni Gundogdu <legatvs@gmail.com>
Merge branch 'tg/0.4__improve_liveleak.lua' into maint-0.4
tests: redirect.t: Update URL for 101greatgoals

Signed-off-by: Toni Gundogdu <legatvs@gmail.com>