Add platform support for nrpe packages
Add platform support for nrpe packages

This change uses a case statement to model the packages
required for basic NRPE checks on a per platform basis.

I prefer this pattern over delegating to other classes
like nrpe_basic::packages::{debian,redhat} to consolidate
all resources in one class and mitigate ordering issues.

This also works more directly with subscriptions and
notifications like Class[nrpe_basic::packages] ~>
Class[nrpe_basic::service]
jeffmccune/jeffmccune-nrpe_basic