add package_manage parameter

[cedriclaudrel]

Hello,

In our puppet environments, we need to manage the sudo package in a separate class.

Pre-v8.0.0, it was possible to avoid conflict by setting package => ''. This is not the case anymore, and due to the move of saz_sudo to a package resource, we cannot achieve the same behavior as before without having a conflict.

This PR adds a new package_manage parameter, set to true by default. Nothing changes by default, and setting this parameter to false simply skips the package resource.

Let me know if it's acceptable and if any change is needed to integrate this :)

Have a great day