(#12244) All forge interactions should be centralized

Before this patch each module application makes direct connection to the
Puppet Forge. This is a maintenance nightmare, any changes to the
Forge API requires changes to all the module applications.

This patch re-factors how we communicate with the Forge. All module
application now use the interface exposed by the lib/puppet/forge.rb
module.

This patch also includes tests for the new forge.rb module, and updates
others to reflect the new behaviour.