Curl-proxy / wget-proxy scripts in Templates so users can add GPG distro keys linked to added external repositories

[adw]

@adw

Seems like we should at least document this on the how to install software page. I just noticed that this section is out-of-date, since it still references changing only the template’s firewall rules , which of course won’t solve anything when the template has no NetVM.

Update "how to install software"