Use homebrew for default package provider on OS X

:ice_cream: 

Via [Chef RFC 016](https://github.com/opscode/chef-rfc/blob/master/rfc016-homebrew-osx-package-provider.md), fixes issue #1709, adding the `homebrew_package` resource with the `homebrew` provider, and setting it as the default for Mac OS X platforms (`mac_os_x`, `mac_os_x_server`). This will still require that homebrew is installed on the system somehow, but doesn't require use of the cookbook if users choose to install via some other method (pre-built images, for example).

Example of this in action: https://gist.github.com/jtimberman/1f0a6fd434a6ecef95da

If a custom default for a property is needed, we're using config for it right now [e.g.](https://github.com/opscode/chef/blob/master/lib/chef/config.rb#L334). Not ideal but... 

I think we should have the config value because while this will work for the existing nodes, new nodes that one is provisioning will not have this info in them since noone is setting it anymore :smile:. A nice to have would be to print a warn message that points people to the config value if cookbook value is set and config value is not set.

Is there a use case where one will need different owner values for different resources? If so then having a resource attribute will be useful.