Add additional features to foremanctl health subcommand

[qcjames53]

Of the default health checks from foreman-maintain, foremanctl health currently implements the following checks:

• services_up
• server_ping
• foreman_tasks/not_paused

Please add the foreman/facts_names check and a sanity-check unit test for the health checks on a working environment. Check if there are any more relevant default checks we missed (or non-default worth including).

Note: the following checks will not need to be migrated:

• foreman_proxy/check_tftp_storage - No foreman proxy support yet.
• foreman_proxy/verify_dhcp_config_syntax - Ditto.
• puppet/verify_no_empty_cacert_requests - Puppet plugins for foreman and smart proxy are not yet compatible with foremanctl; work is underway to add support in the future.
• system_registration - This self-registration concern isn't valid for an upstream centos9 container, to the best of my knowledge.