feat(netxlite): implements NS queries (#734)

This diff has been extracted from https://github.com/bassosimone/websteps-illustrated/commit/eb0bf38957e79fbad198fcdc9f9c7b36f61a8e2c.

See https://github.com/ooni/probe/issues/2096.

While there, skip the broken tests caused by issue
https://github.com/ooni/probe/issues/2098.

internal/cmd/apitool/main_test.go

@@ -11,6 +11,7 @@ func init() {
 }
 
 func TestCheck(t *testing.T) {
+	t.Skip("see https://github.com/ooni/probe/issues/2098")
 	*mode = "check"
 	main()
 }