* discovery: expose HTTP client options to discoverers Signed-off-by: Robert Fratto <robertfratto@gmail.com> * discovery/http: use HTTP client options for created client Signed-off-by: Robert Fratto <robertfratto@gmail.com> * scrape: use a list of HTTP client options instead of just dial context Signed-off-by: Robert Fratto <robertfratto@gmail.com> * discovery: rephrase comment Signed-off-by: Robert Fratto <robertfratto@gmail.com>