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/cloudflare_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
 func TestIPLookupWorksUsingcloudlflare(t *testing.T) {
@@ -16,6 +17,7 @@ func TestIPLookupWorksUsingcloudlflare(t *testing.T) {
 		http.DefaultClient,
 		log.Log,
 		model.HTTPHeaderUserAgent,
+		netxlite.NewStdlibResolver(model.DiscardLogger),
 	)
 	if err != nil {
 		t.Fatal(err)