Document the distinction between --install-cert and --deploy, if any

[loyeyoung]

It seems that --install-cert and --deploy do the same thing, except that --deploy is more specifically aimed at particular services.

If I am wrong, please advise. If they do different things, consider documenting the difference in the wiki.

If they do the same thing, consider combining the two into one command.

[Neilpang]

yes, they are very simlar.

--install-cert was born earlier than deploy. it's more powerful to control where to install the cert/key, and how to restart the service to reload the new cert.

deploy can only work with the supported deploy hooks.

If your service is supported in the deploy hooks, please use the deploy hook.
otherwise, use the --install-cert