install.sh script

Gost can be installed [like this](https://github.com/go-gost/gost/blob/master/README_en.md#install-script):

```bash
# install latest from [https://github.com/go-gost/gost/releases](https://github.com/go-gost/gost/releases)
bash <(curl -fsSL https://github.com/go-gost/gost/raw/master/install.sh) --install
```

Would be nice to have such a install.sh script for realm too.