Initial draft for ps module resource

So this is the source of where to get the module? And so is download_from? Maybe easiest to just let this be one attribute -- e.g. `source`, and see if it is a url (file: or http: / https: schemes), otherwise treat it like a file system path. What do package resources do (e.g. `apt_package`) -- this is essentially a package resource. We may actually want to make it inherit from `Chef::Resource::Package`...