Add class to configure generating certificates

[ehelms]

The intent of this class is to allow generating any number of the sets of certificates from this module in a simple way. This is also a way to work around the fact that parsing params by Kafo doesn't cleanly work on classes such as certs::apache (see #424).

[ehelms]

See theforeman/foreman-installer#935 for example of how this is intended to be used.

[ekohl]

I didn't see this before, but I recall a long time ago that I already discussed something like this with @timogoebel. Then we talked about making it a define so you could easily declare it for multiple hosts.

In effect this is a more configurable version of certs::foreman_proxy_content.

We could even go a step further and generalize it to make certs_tar an optional parameter.

[ehelms]

@evgeni What do you think about merging this in to then proceed with the certs command in the installer?

[evgeni]

@evgeni What do you think about merging this in to then proceed with the certs command in the installer?

yes please

[ehelms]

@evgeni What do you think about merging this in to then proceed with the certs command in the installer?

yes please

Smash that review button.

[evgeni]