fix(geolocate): always use netxlite functionality (#976)

This change ensures that, in turn, we're able to "remote" all the traffic generated by the `geolocate` package, rather than missing some bits of it that were still using the standard library and caused _some_ geolocations to geolocate as the local host rather than as the remote host.

Extracted from https://github.com/ooni/probe-cli/pull/969, where we tested this functionality.

Closes https://github.com/ooni/probe/issues/1383 (which was long overdue).

Part of https://github.com/ooni/probe/issues/2340, because it allows us to make progress with that.

internal/engine/geolocate/invalid_test.go

@@ -12,6 +12,7 @@ func invalidIPLookup(
 	httpClient *http.Client,
 	logger model.Logger,
 	userAgent string,
+	resolver model.Resolver,
 ) (string, error) {
 	return "invalid IP", nil
 }