RFE: Yum/Apt repo and GPG key management optional

[ghost]

I would be really nice to have:

• Yum/Apt repo management optional in this module.
• GPG key management optional

The goal that we have is to have the RPM package in our own YUM repo and have it signed with our GPG key. The duo_unix puppet module is unable to accommodate at this time.

[ghost]

PR #18 looks like it could be a good contender to optionally manage the package repo.