refs #8432 - change foreman.url to proxy.url, support sending to proxy

1) rename foreman.url to proxy.url
2) add a parameter ```proxy.type``` (which should be set to ```proxy``` for smart proxy)
3) if ```proxy.type == 'proxy'``` then alter the url to smart proxy url.
This can be written as: `cmdline 'proxy.type', 'proxy'`

Can we add an extra check? Because when upgrading, I've missed that `foreman.url` is now named `proxy.url` and it was failing and I was not pretty sure how to fix this for few minutes. Can we add a simple check if proxy.type is "proxy" and "proxy.url" is not present, issue a bold warning to the logs like:

    *** Proxy type is #{type} but #{type}.url was not set, this will likely fail ***