support git remotes that need http basic auth

using git credential to get the password

One thing this doesn't do is wrap the password prompting inside the prompt
action. So with -J, the output can be a bit garbled.

Command/AddUrl.hs

@@ -261,7 +261,7 @@ downloadWeb addunlockedmatcher o url urlinfo file =
 	go =<< downloadWith' downloader urlkey webUUID url (AssociatedFile (Just (toRawFilePath file)))
   where
 	urlkey = addSizeUrlKey urlinfo $ Backend.URL.fromUrl url Nothing
-	downloader f p = downloadUrl urlkey p [url] f
+	downloader f p = Url.withUrlOptions $ downloadUrl urlkey p [url] f
 	go Nothing = return Nothing
 	-- If we downloaded a html file, try to use youtube-dl to
 	-- extract embedded media.