Support creation of multiple resolv.conf files on the same machine

Why you ask?
I'm working with jails on FreeBSD.  In general I'm striving to configure a new jail from "inside" itself (and automatically, via Puppet), but I can't do much of anything that involves networking if resolv.conf isn't configured correctly.  So, I am creating a new jail, and then adding an appropriate resolv.conf file into that jails filesystem.  I wanted to use resolv_conf to do so, but as a class, at a fixed location, I was stuck.  So I changed it as you can see.

Perhaps there is a less drastic way to do what I needed, but I couldn't figure out how to get access to the variables in params.pp for default values of arguments to create (formerly resolv_conf)

Obviously this is a big breaking change, and I won't be surprised if you refuse it, but I do need something like this, so if not, I'll just have to live with my own fork.