Add comment in manage_unit deployed files

[traylenator]

Pull Request (PR) description

It's useful to see clearly see that files deployed with puppet are deployed with puppet.

Add a comment to top of files deployed by systemd::manage_unit and systemd::manage_dropin.

e.g

systemd::manage_unit{'redis@.service':
  ensure          => present,
  unit_entry    => {
    'Description' => 'redis server instance on port %i',
   },
  service_entry => {
    'Type'      => 'simple',
    'User'      => 'redis',
    'Group'     => 'redis',
    'ExecStart' => '/usr/bin/redis-server /etc/redis/redis_%i.conf',
    'ExecStop'  => '/usr/bin/redis-cli -p %i shutdown',
    'PIDFile'   => '/run/redis/%i.pid',
  },
}

will now deploy /etc/systemd/system/@redis@.service with a first line of:

# Deployed with puppet

[traylenator]

We could put the comment as an additional description:

[Unit]
Docs=This unit is at least partially manged by puppet

And it would show up in a status, something like:

$ systemctl status sshd
○ sshd.service - OpenSSH server daemon
     Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled; preset: disabled)
    Drop-In: /usr/lib/systemd/system/service.d
             └─10-timeout-abort.conf
     Active: inactive (dead)
       Docs: man:sshd(8)
             man:sshd_config(5)
             This unit is at least partially manged by puppet
            

cool but probably a bit intrusive.

[traylenator]

If possible and then I'll make a release.

[bastelfreak]

I would be fine with a comment or a description, whatever you prefer.

[traylenator]

Morning,
I think stick with the comment as is. If we add to the description it gets ambiguous when the description is reset with an '' value.