pkg installer beautification for chef & chefdk

This PR arranges the pkg packaging resources for chef & chefdk. It depends on:

https://github.com/opscode/omnibus-ruby/pull/135
https://github.com/opscode/omnibus-software/pull/163

/cc: @opscode/client-eng, @opscode/release-engineers 

This these changes the new pkg installers are looking like: 

![screen shot 2014-04-08 at 11 02 00 pm](https://cloud.githubusercontent.com/assets/1695955/2662744/94e8c438-c044-11e3-94f6-a13cbef737b0.png)

![screen shot 2014-04-09 at 2 41 57 pm](https://cloud.githubusercontent.com/assets/1695955/2662747/98d08310-c044-11e3-924d-989aa65567b1.png)