[WIP] Config labels

*The below conversation has been hidden unintentionally because of the comment change:*

> Ben Parees
> why wouldn't we add a labels field if none exists?
> 
> Vojtech Vitek
> I think we can't add Labels to the object that doesn't have this field in it's declaration. If the field is declared but empty, then yes.
> 
> Ben Parees
> can't for technical reasons, or can't because you think it's a bad behavior to do it?
> 
> Vojtech Vitek
> 1. Not sure. I'd have to try..
> 2. Yes, I thought setting Labels to the objects that doesn't define any such field (eg. Template, Config, Image, ImageRepositoryMapping etc.) would be a bad practice. I think the problem would grow drastically, if I had to loop over the the objects recursively. And I guess we might be doing this eventually. Then, all of the generated json Objects would have the "Labels" field, even the "Labels".