Include chef-dk in Chef DK omnibus packages

# Remove references to CHEF_GIT_REV & OHAI_GIT_REV
# Add chef-dk gem into chefdk software definition
# Add chef-dk as an app to be verified by "chef verify"
# Convert chef component to be similar to the other Chef DK components. 

@opscode/client-eng thoughts? 
@lamont-granquist would last one break client packaging? I think not but want to double check.