Support Foreman hosts that are unmanaged

[walkamongus]

This adds support for unmanaged hosts in Foreman. I also encountered what appeared to be a bug where the data sent to Foreman was repeated at the top-level as well as in thehost key.

Foreman (v1.17) was receiving:

{"build"=>false, "comment"=>"", "domain_id"=>nil, "environment_id"=>"1", "hostgroup_id"=>"1", "managed"=>false, "name"=>"host.example.org", "operatingsystem_id"=>nil, "apiv"=>"v2", "host"=>{"build"=>false, "comment"=>"", "managed"=>false, "name"=>"host.example.org", "domain_id"=>nil, "environment_id"=>"1", "hostgroup_id"=>"1", "operatingsystem_id"=>nil}}

whereas it should only get

{"host"=>{"build"=>false, "comment"=>"", "managed"=>false, "name"=>"host.example.org", "domain_id"=>nil, "environment_id"=>"1", "hostgroup_id"=>"1", "operatingsystem_id"=>nil}}

and the extra data was causing it to throw a Hostgroup not found by id error.