Add hammer command to represent a new resource as a JSON file in the Git repo

Problem with apipie-bindings:

```
agrant@foregit:~$ hammer add -r architectures -f ceva
Creating JSON representation of architectures resource in Git repo...
Creating resource architectures with attributes: {"architecture"=>{"name"=>"x86", "operatingsystem_ids"=>[]}} to Foreman...
Error: 422 Unprocessable Entity

vagrant@foregit:~$ hammer add -r architectures -f ceva
Creating JSON representation of architectures resource in Git repo...
Creating resource architectures with attributes: {"name"=>"x86", "operatingsystem_ids"=>[]} to Foreman...
Error: ApipieBindings::MissingArgumentsError: name

vagrant@foregit:~$ hammer add -r architectures -f ceva
Creating JSON representation of architectures resource in Git repo...
Creating resource architectures with attributes: {"architectures"=>{"name"=>"x86", "operatingsystem_ids"=>[]}} to Foreman...
Error: ApipieBindings::MissingArgumentsError: name
```