lower version for dependence puppetlabs-apt does not install gnupg

Since we bumped dependencie version for puppetlabs-apt module, we do not ensure gnupg is installed anymore. Since puppetlabs-apt version v7.2.0, gnupg is installed but this module.

But Gitlab sources installer, at least with Debian OS family, requires gnupg installed.

For Puppet module puppetlabs-apt, the lower version in metadata.json is currently >= 5.0.0. This version does not manage gnupg installation.

Probably best way is to use ensure_packages() or ensure_resource() functions in adullact-gitlabrunner:

• This requires puppetlabs-stdlib >= 4.24.0.
• This permits to not be dependent of module puppetlabs-apt for gnupg management.
• This permits to not modify lower limit for module puppetlabs-apt (v7.2.0 is quite recent).
• This will facilitate the work to make this module compatible with RedHat OS family.