Add check_package_update_by_ssh

[lermit]

Hi,

This PR add a new check for package update.

This check work with all Debian based distro and Red Hat, CentOS and Fedora.

The threshold values can be set to -1 to disable alerting (in case you want use this script only for performance data).

  -w WARNING, --warning=WARNING
                        Warning value for upgradable package, as 2 values.
                        First one for security upgrade, second one for
                        standard. If you set one of this value to -1 this will
                        disable the check. Default : 0,-1
  -c CRITICAL, --critical=CRITICAL
                        Critical value for upgradable package, as 2 values.
                        First one for security upgrade, second one for
                        standard. If you set one of this value to -1 this will
                        disable the check. Default : 1,-1

Fill free to comment.

Regards

[naparuba]

Looks great, thanks :)