(PUP-2285) Integrating the recommended README template

Prior to this commit, `puppet module generate` would create a simplistic
README file for the new module.  This change integrates the README
template we publicly recommend people use to document their modules
(http://docs.puppetlabs.com/puppet/latest/reference/modules_documentation.html).
Merge pull request #2539 from pvande/task/master/pup2285_add_better_readme_to_module_skeleton

(PUP-2285) Integrating the recommended README template