Util: Migrate func/client.php

To:

- Util\HttpUtil
- Util\Ip
Base: Better test case with @codeCoverageIgnore
Util: Migrate func/crypt.php

To: Util\McryptSmplIv
Util: Migrate func/download.php

To: Util\HttpUtil::download(), downloadFile()
Util: Migrate func/env.php, ecl.php

To: Util\Env