Remove restriction on package_ensure and conditionally require puppetlabs-products repo

[treydock]

• Allow package_ensure to be any value to match allowed values for Package type and to allow specifying specific versions
• Add manage_puppetlabs_repo parameter to conditionally require Yumrepo[puppetlabs-products] before installing facter
• Added dependency for module stahnma/puppetlabs_yum

This is likely not best way to handle the dependency on the puppetlabs repo, but the removal of restriction on values for package_ensure would be very useful to ensure specific versions are installed across servers.

[ghoneycutt]

@treydock thanks for your contribution. I cannot accept the code to include puppetlabs's yum repo as it is not general enough of a use case and adds extra dependencies for yum that many environments do not need. As a rule, I don't put repo management in with specific modules, only with modules meant to manage repos.