Metaparameter for passing environment information (like in 'exec' resource)

It would be handy to pass an environment parameter to multiple types, similar to how it is done for exec. Sometimes, because it only exists in exec, folks will resolve to using an exec resource instead of a more native resource solely because that resource type is missing environment and similar other features. So instead of having folks fall into the exec anti-pattern out of constraints, we should open that up.